Space videos: 
https://mashable.com/article/4k-space-videos/

Change computer screen color by time: 
https://justgetflux.com/

You're the bomb: 
http://thebomb.lol/

Did CIA Observed 'Life On Mars' In 1984? 
https://www.ladbible.com/news/news-weird-technology-declassified-documents-suggest-cia-observed-life-on-mars-in-1984-20210218

Legal definitions: 
https://definitions.uslegal.com/

Hear a color: 
https://artsandculture.google.com/experiment/play-a-kandinsky/sgF5ivv105ukhA?hl=en

How to sit on air: 
https://digg.com/video/engineer-demonstrates-how-to-pull-off-the-sitting-in-the-air-trick

Munch declared "Can only have been painted by a madman" on The Scream: 
https://www.cnn.com/style/article/edvard-munch-the-scream-inscription-scli-intl/

Small particle accelerator: 
https://theconversation.com/forget-the-large-hadron-collider-our-team-has-designed-a-particle-accelerator-the-size-of-a-large-room-155433

Convert audio formats:
https://convertio.co/audio-converter/

VIdeos of the Capital attack:
https://thepatr10t.github.io/yall-Qaeda/

Unbelievable Facts:
https://unbelievablefactsblog.com/

Get crows to move on:
https://www.youtube.com/watch?v=nb0CAqiImZE

Python in 75 minutes:
https://youtu.be/VchuKL44s6E

Secret menus:
https://secretmenus.com/

SEO Guide:
https://yoast.com/complete-beginner-guide-to-seo/

The International Obfuscated C Code Contest: 
https://www.ioccc.org/

Chicken slapping: 
https://youtu.be/68L6JA_CnmU

Free Machine Learning course:
https://www.coursera.org/learn/machine-learning

Real-time Bitcoin monitor:
https://blocks.wizb.it/

Extremely buggy web app with 100 vulnerabilities:
http://www.itsecgames.com/

If you are turned into stone:
https://randomthingstodo.com/13-things-to-do-if-you-suddenly-get-turned-into-stone

Computer-generated click bait headlines:
http://clickotron.com/

Isolated people:
https://www.survivalinternational.org/uncontactedtribes

Let's start the new year off right:
http://attackofthecute.com/

Online board games: 
https://en.boardgamearena.com/

Windows text expander: 
https://www.phraseexpress.com/

Intiutive convolution: 
https://betterexplained.com/articles/intuitive-convolution/

Web Assembly: 
https://webassembly.org/

Open source logic analyzer software:
 https://sigrok.org/

Colorize old photos: 
https://www.myheritage.com/incolor

RAM disk for Windows:
https://sourceforge.net/projects/imdisk-toolkit/

Family dog education: 
https://www.thefamilydog.com/stop-the-77/

Boat with no moving parts: 
https://www.youtube.com/watch?v=nFsiydplCtw

Phrases with racist pasts: 
https://medium.com/an-injustice/7-racist-slurs-which-you-should-drop-from-your-vocabulary-885c56ba97ae

Open source hardware: 
https://github.com/chipsalliance

Nobody has measured the speed of light: 
https://www.youtube.com/watch?v=pTn6Ewhb27k

Privacy plan: 
https://securityplanner.consumerreports.org/

Uncontacted tribes:
https://www.survivalinternational.org/uncontactedtribes

Explore debates:
https://www.kialo.com/

Locate cell towers:
https://www.cellmapper.net/map

Pressure washer art: 
https://digg.com/video/artist-uses-pressure-washer-to-paint-driveway-mural

Free video processing software for astronomy: 
https://www.astronomie.be/registax/

Linux on your Android phone: 
https://hackaday.com/2020/10/07/linux-fu-the-linux-android-convergence/

Moving with pets: 
https://www.mymove.com/moving/guides/moving-pets-safely/

122 Pythagorean Theorem proofs: 
https://www.cut-the-knot.org/pythagoras/

Trimming a 100-foot palm: 
https://digg.com/video/guy-rides-palm-trees-cut-fronds

Magpie janitor: 
https://www.instructables.com/Train-Wild-Birds-to-Exchange-Litter-for-Food/

G-suite cheat sheets: 
https://www.customguide.com/cheat-sheet/g-suite-for-business-cheat-sheets.pdf

What's happening on the internet: 
https://www.visualcapitalist.com/every-minute-internet-2020/

Slave voyages:
https://www.slavevoyages.org/

Accelerate Python for scientific computing:
https://numba.pydata.org/

Collaborative search:
http://searchteam.com/

Search engine with privacy:
https://www.qwant.com/

Defecation education:
https://www.youtube.com/watch?&v=0Jjr21lFLCY

Free software:
https://www.ilovefreesoftware.com/

Detailed cell phone specs: 
https://www.gsmarena.com/

Windows minus spyware:
https://ameliorated.info/

Google keywords: 
https://lsigraph.com

Science news: 
https://www.eurekalert.org/

Earthquake map: 
https://earthquake.usgs.gov/earthquakes/map/

Draw your signature:   
https://createmysignature.com/http://en.wikipedia.org/wiki/List_of_open_source_software_packages

How much TP do you need?
https://tpfreedom.com/  

Break glass to sound alarm:
https://theuselessweb.site/breakglasstosoundalarm/

Map of the internet:
https://internet-map.net/

The 5,000 best:
http://5000best.com/

Unusual Wikipedia articles:
https://en.wikipedia.org/wiki/Wikipedia:Unusual_articles

Spoiled photos:
https://www.spoiledphotos.com/

Word counter:
http://www.writewords.org.uk/word_count.asp

Shorten URLs:
https://is.gd/

History of a name:
https://www.behindthename.com/

Webcam toy:
https://webcamtoy.com/

Strobe illusion:
https://strobe.cool/

Move your mouse and draw a garden:
https://drawing.garden/

Potato or tomato?
http://potatoortomato.com/

Click on the screen:
http://www.yesnoif.com/

Smash walls:
https://smashthewalls.com/

Make art:
https://jacksonpollock.org/

Bouncing cats;
https://cat-bounce.com/

Ephemeral file sharing:
https://www.file.io/

Interesting book covers:
https://alwaysjudgeabookbyitscover.com/

Compare country sizes:
https://thetruesize.com/

Boot many ISOs from one USB:
https://www.ventoy.net/en/index.html

How animals eat their food:
https://www.youtube.com/watch?&v=qnydFmqHuVo

Is my computer on fire:
http://www.ismycomputeronfire.com/

Roomba quest:
https://st33d.itch.io/roomba-quest

:Screen-play:
http://www.rememberspook.com/#

Innovation videos:
https://www.tis.tv/

Free ebooks:
https://www.onread.com/

How much caffeine is safe?
https://www.caffeineinformer.com/death-by-caffeine/

Fantasy creatures:
https://fruitbatphoenix.com/

Invisible Windows folders:
https://www.maketecheasier.com/create-invisible-folders-windows/

Curated list of starutup venture capitalists:
https://techcrunch.com/the-techcrunch-list/

Quackwatch:
https://quackwatch.org/

Covid event planning risk:
https://covid19risk.biosci.gatech.edu/

SSD failures:
https://www.makeuseof.com/tag/5-warning-signs-ssd-break-fail/

Networked multiple monitors:
https://spacedesk.net/

Terminus SSH client:
https://termius.com/

196h Century European maps: 
https://mapire.eu/en/

UFO sitings:
https://ufostalker.com/

Meteor shower calendar: 
https://www.amsmeteors.org/meteor-showers/meteor-shower-calendar/

Cats help you live longer:
https://www.upworthy.com/4-brilliant-ways-cats-are-secretly-helping-their-owners-live-healthier-lives

Keyboard fruit ninja:
https://flavourmachine.com/fruit/

Free search of public records:
https://www.brbpublications.com/freeresources/Pubrecsites.aspx

Be happy:
https://happy.goodnightjournal.com/

Make pop-up cards:
https://peterdahmen.de/category/anleitungen/

Talking to children about internet issues:
https://www.keepitrealonline.govt.nz/

100,000 generated faces:
https://mkorostoff.github.io/hundred-thousand-faces/

Anonymize protesters' faces:
https://everestpipkin.github.io/image-scrubber/

Faces from drawings:
http://geometrylearning.com/DeepFaceDrawing/

German tap water brought to Evian:
https://digg.com/video/german-tap-water-comes-to-evian

Edit videos:
https://www.openshot.org/

Realistic Santa Claus:
https://cheezburger.com/103373057/a-way-too-realistic-santa-clause-drawn-in-ms-paint

Windows USB driver installer:
https://zadig.akeo.ie/

Free photos with transparent backgrounds: 
https://photos.icons8.com/transparent

Structured thinking: 
https://forge.medium.com/learn-structured-thinking-in-3-minutes-550a2dc2123c

Use Gmail offline:
https://www.maketecheasier.com/how-to-use-gmail-offline

Image-aware cropping:
https://29a.ch/2014/04/03/smartcrop-content-aware-image-cropping/

U.S. Library of Congress:
https://www.loc.gov/

Color wheel memory game:
https://color.adobe.com/create/color-wheel-game

Cuneiform writing:
https://www.youtube.com/watch?v=PfYYraMgiBA

Design your home in 3D:
https://www.homestyler.com/int/

Find an apartment:
https://www.padmapper.com/

Create a flipbook:
https://flipanim.com/

Track email you send:
https://www.getnotify.com/

Remove vocals from a song:
https://www.remove-vocals.com/

Time stretch an audio file:
https://29a.ch/timestretch/

Trip through a hand drawn landscape - use right/left arrow keys:
https://alexanderperrin.com.au/paper/shorttrip/#

Shipping container building:
https://www.youtube.com/watch?v=Ti5iRtYYqJg

Draw a line, find a place on earth:
https://lines.chromeexperiments.com/

K-mart music:
https://archive.org/details/attentionkmartshoppers

Covid 19 dashboard:
https://ncov2019.live/data

Search Trump's tweets, speeches, and policies:
https://factba.se/trump

Graph functions:
https://www.desmos.com/calculator

SpaceX docking simulator:
https://iss-sim.spacex.com/

Make paper airplanes:
https://digg.com/video/how-to-fold-paper-airplane

Create a universe for $3.95:
http://cheapuniverses.com/

Forgotten songs:
https://forgotify.com/

Sun Dance: 
https://digg.com/video/this-8k-film-made-with-a-weeks-worth-of-data-from-nasas-solar-dynamics-observatory

Are you tone deaf?
https://www.themusiclab.org/quizzes/td

Free video builder for small businesses: 
https://www.makeuseof.com/tag/youtube-video-builder-for-businesses/

Convert between markup languages: 
https://pandoc.org/

Free movies: 
https://vole.wtf/voleflix/

Free and secure messaging: 
https://tox.chat/

Compress PDF files: 
http://www.freepdfcompressor.com/

Commercial games released as free software: 
https://en.wikipedia.org/wiki/List_of_commercial_video_games_released_as_freeware

Reverse dictionary: 
https://www.onelook.com/thesaurus/

Free invoice generator: 
https://invoice-generator.com/

50 GB free storage and secure file sharing: 
https://mega.nz/

Make a podcast
https://anchor.fm/

Computer shortcuts
https://www.computerhope.com/shortcut.htm

Build a one page website:
https://carrd.co/

PDF compressor:
http://www.freepdfcompressor.com/  

Old apps:
http://www.oldapps.com 

Private Snafu: 
https://www.youtube.com/playlist?list=PLdcDAOVAAGTQzfl4Sq-1Q1i5Yg4a77l9y

Is this a cat? 
http://isthisacat.com

Remove video background:
https://www.unscreen.com/

Exploitable Linux apps: 
https://gtfobins.github.io/

Letter generator: 
https://www.letter-generator.org.uk/

Build business websites: 
https://webflow.com/

Cat facts: 
https://petpedia.co/cat-facts/

Folding paper airplanes:
https://www.youtube.com/watch?v=HVjIBZG_QrY

Scrape web pages without getting caught: 
https://medium.com/datadriveninvestor/how-to-not-get-caught-while-web-scraping-88097b383ab8

Password generator: 
https://xkpasswd.net/s/

States other states love and hate:
https://digg.com/2020/favorite-state-of-each-state-map

Six-minute workouts: 
https://www.nytimes.com/2020/02/18/well/in-6-minutes-you-can-be-done-with-your-workout.html

Comparison of asteroid sizes:
https://www.youtube.com/watch?v=bSkPNMjRRio

Learn new things: 
https://tangi.co/

The Black Vault: 
https://theblackvault.com

Brown is weird: 
https://digg.com/video/brown-color-weird

Free Autodesk Sketchbook
https://sketchbook.com/

Windows subsystem for Linux:
https://adamtheautomator.com/windows-subsystem-for-linux/

Draw Unicode characters:
http://shapecatcher.com/

Epic Fail:
http://www.epicfail.com/

Grafitti:
http://www.picturesofwalls.com/

Self-starting siphon:
https://www.youtube.com/watch?v=4SEv_GxAo70

Free finite field analysis: 
https://quickfield.com/

Collaborative web coding: 
https://glitch.com/

Free Python resources: 
https://www.fromdev.com/2014/03/python-tutorials-resources.html

Bit hacks: 
https://graphics.stanford.edu/~seander/bithacks.html

Font for programmers: 
https://www.jetbrains.com/lp/mono/#143-languages

Share text and images: 
https://justpaste.it/

Airport WiFis: 
http://bit.ly/airportwifimap

Chrome browser scratchpad: 
https://lifehacker.com/turn-any-browser-window-into-a-quick-edit-notepad-5980134

Unbiased fact check site #6: 
https://leadstories.com/

Unbiased fact check site #3:
https://www.politifact.com/

Search online historic newspapers:
https://elephind.com/

This foot does not exist: 
https://thisfootdoesnotexist.com/

Manually face tag photos in Google: 
https://www.maketecheasier.com/tag-face-manually-google-photos/

Organize your files: 
http://www.dropitproject.com/

Free voice and text chat: 
https://discordapp.com/

Windows photo gallery: 
https://www.microsoft.com/en-us/p/gallery-hd/9wzdncrfjchh

Another Windows photo editor: 
https://www.microsoft.com/en-us/p/fhotoroom/9wzdncrfj3m9

Windows photo editor: 
https://www.microsoft.com/en-gb/p/fotor/9wzdncrfhw5q

Download free books: 
https://centslessbooks.com/

Open source quantum computing: 
https://qiskit.org/

Programming with arrays: 
https://fastarray.appspot.com/index.html

Python for Excel: 
https://www.xlwings.org/, and
https://ericremoreynolds.github.io/excelpython/

Lead story fact check: 
https://leadstories.com/

Truth or fiction? 
https://www.truthorfiction.com/

Voter fact check: 
https://www.factcheck.org/

Political fact check: 
https://www.politifact.com/

Fact check: 
https://www.snopes.com/

Media bias check: 
https://mediabiasfactcheck.com/

View .brd files:  
http://openboardview.org/

Free psychology education: 
https://www.tpsgc-pwgsc.gc.ca/citeparlementaire-parliamentaryprecinct/decouvrez-discover/drapeaux-demander-flags-request-eng.html#a1

Fix Windows 10 issues: 
https://www.thewindowsclub.com/fixwin-for-windows-10

Tweak Windows 10: 
https://www.thewindowsclub.com/ultimate-windows-tweaker-4-windows-10

Control your Windows 10 privacy settings: 
https://www.oo-software.com/en/shutup10

Dummy image generator: 
https://dummyimage.com/

Generate ASCII art:
http://www.glassgiant.com/ascii/

Fighting pixels:
http://pixelsfighting.com/

Is my computer on?
http://www.ismycomputeron.com/

Random color:
http://randomcolour.com/

What is the highest frequency sound you can hear?
http://onlinetonegenerator.com/hearingtest.html

Get an arbitrary award:
http://arbitraryawards.com/

Free art lessons:
https://artyfactory.com/art-lessons.html

Sorting set to dance: 
https://www.youtube.com/user/AlgoRythmics

Researchers' conflict of interest: 
https://projects.propublica.org/dollars-for-profs

Video surveillance software: 
https://www.contaware.com/

Data structures and algorithms: 
https://opendsa-server.cs.vt.edu/ODSA/Books/Everything/html/index.html 

Mount virtual drives: 
https://www.elby.ch/en/products/vcd.html 

Images of the sun:
https://sdo.gsfc.nasa.gov/data/

Brain-to-brain communication:  
https://www.nature.com/articles/s41598-019-41895-7.pdf

Edit triangular meshes:
http://www.meshlab.net/

3D scan from camera photos: 
https://alicevision.org/

Our universe:
https://www.seeker.com/series/focal-point

Free, accredited university:
https://www.uopeople.edu/

Break big ideas into manageable pieces:
https://workflowy.com/

What to say to fill the silence:
https://help-fill-the-silence.tumblr.com/

Binwalk firmware analysis tool:
https://www.basicinputoutput.com/2016/08/the-binwalk-firmware-analysis-tool.html

How to cut every fruit:
https://digg.com/video/learn-how-to-slice-pretty-much-every-fruit-correctly-so-you-dont-make-a-huge-mess

Windows Hot Key addon: 
https://www.autohotkey.com/

101 free fonts: 
https://www.shutterstock.com/blog/top-free-fonts-designers

Electronics for beginners: 
https://www.build-electronic-circuits.com/electronics-for-beginners/

Learn Linux: 
https://linuxjourney.com/

Travel guides: 
https://freetravelguides.com/

Free vector graphics:
https://www.vecteezy.com/

Memetics - A military growth industry: 
https://apps.dtic.mil/dtic/tr/fulltext/u2/a507172.pdf

How to get off of Google:
https://www.zdnet.com/article/goodbye-google-why-and-how-to-take-back-your-privacy/

Declutter your inbox: 
http://subscriptionzero.com/

Draw with an online turtle: 
https://turtletoy.net

Earthquake Emergency Handbook: 
https://www.wsspc.org/wp-content/uploads/2017/01/Handbook_FINAL_New.pdf

SAS survival manual: 
http://www.landsurvival.com/downloads/SAS%20Survival%20Handbook.pdf

Army survival manual:   
https://thesurvivalmom.com/wp-content/uploads/2015/03/FM_21-76-US-army-survival-manual.pdf

Survival guide: 
https://www.csustan.edu/sites/default/files/SRC/documents/SurvivalSkills.pdf

Paper phone: 
http://specialprojects.studio/project/paper-phone/

Crop a video: 
https://clideo.com/crop-video

Neural network completes your text: 
https://talktotransformer.com/

IC die photos:
https://zeptobars.com/en/

Warp speed in the solar system: 
https://gfycat.com/showyagedflyingfox-james-odonoghue-science-fiction-space-travel

Free stock footage: 
https://www.videvo.net

Create a ransom note: 
http://www.ransomizer.com

Find emergency rooms and their rating: 
https://projects.propublica.org/emergency/

Black Market Prices: 
https://cdn.armor.com/app/uploads/2018/10/2019-Q3-Report-BlackMarket-SinglePages-1.pdf    

Free PDF editor and converter: 
https://www.starzsoft.com/pdf-converter/

Learn to hack from scratch:
https://getnewcourses.com/learn-hacking-using-android-from-scratch/

Microsoft's free Python course: 
https://www.youtube.com/playlist?list=PLlrxD0HtieHhS8VzuMCfQD4uJ9yne1mE6

Fix a Zip archive: 
http://www.essentialdatatools.com/products/objectfixzip/

Visualizing the speed of light: 
https://gfycat.com/perkydetailedchamois

Uncheck boxes to install superfluous software: 
https://unchecky.com/

Free WannaCryFake ransomware decryption tool:
https://blog.emsisoft.com/en/34156/emsisoft-releases-free-decryptor-for-wannacryfake-ransomware/

Drug/supplement interaction checker: 
https://supp.ai/

Airport WiFi passwords: 
https://considerable.com/map-wifi-passwords-airports/

Personalized meal plans: 
https://www.eatthismuch.com

Instagram highlight pack: 
https://www.shutterstock.com/blog/free-instagram-highlights-covers

Non-profit identity theft help: 
https://www.idtheftcenter.org

AI analysis of your face: 
https://imagenet-roulette.paglen.com/

Car problem noises:
http://mycarmakesnoise.com/full-sound-library/

Online theramin:
https://femurdesign.com/theremin/

Build interactive fiction:
http://textadventures.co.uk/quest/

A century of global surface temperatures:
http://students.washington.edu/aodhan/webgl_globe.html

Bible's traditions in context: 
https://biblebrisket.files.wordpress.com/2014/01/exploring-genesis-the-bibles-ancient-traditions-in-context.pdf

Sentence dictionary: 
https://www.foboko.com/sentence-dictionary/

See colors that aren't there: 
https://faculty.washington.edu/chudler/benham.html

Drench game:
http://www.flashbynight.com/drench/

Shark/dolphin/seal tracker:
https://www.ocearch.org/tracker/

285,000 companies at the same 2-story building: 
https://www.youtube.com/watch?v=b00j2aCT6Ug

AI-generated inspiration
https://inspirobot.me/

Cutlist optimizer:
http://www.cutlistoptimizer.com/

Cube within a cube within a cube:
https://youtu.be/AuS6HDHc7XE

Song fingerprint: 
https://song-visualizer.firebaseapp.com

Convert to/from PDF:
https://pdf.to/

Keyboard music:
https://patatap.com

Urgent care or ER?
https://www.indigourgentcare.com/blog/the-right-place-for-the-right-care-urgent-care-vs-emergency-room

Calming videos:
https://napflix.tv/

What language is that?
https://lingyourlanguage.com/

Summarize any article:
https://tldr.hackeryogi.com/

Secure e-mail:
https://tutanota.com/

The roots of slavery:
https://www.nytimes.com/interactive/2019/08/14/magazine/1619-america-slavery.html

Online Encyclopedia of Integer Sequences:
https://oeis.org/?language=english

Technology news:
https://www.techmeme.com/

Programming instruction:
https://internetingishard.com/

Free mechanical CAD program:
https://www.rs-online.com/designspark/mechanical-software

Segregation and racist artifact museum:
https://www.ferris.edu/jimcrow/what.htm

Journey Planet:
http://journeyplanet.weebly.com/

Give your teddy bear a vacation:
http://unagi-travel.net/

All about toilets:
https://toilet-guru.com/

Calculators for construction, woodworkers, etc.:
https://www.blocklayer.com/

World's most relaxing song:
https://www.forbes.com/sites/jordanpassman/2016/11/23/the-worlds-most-relaxing-song/#7b895e8b2053

Known exoplanets:
https://exoplanetarchive.ipac.caltech.edu/

Tool to check and fix 3D models:
https://www.microsoft.com/en-us/p/3d-builder/9wzdncrfj3t6

3D design models:
https://www.myminifactory.com/

Auto VIN check:
https://www.vincheckpro.com/vin-go

Making cookie cutters:
https://www.youtube.com/watch?v=k66fqXttgpE

When can you reuse a calendar:
https://www.whencanireusethiscalendar.com/

Federal Reserve comic book:
https://www.newyorkfed.org/medialibrary/media/outreach-and-education/comic-books/NewYorkFed-StoryoftheFederalReserveSystem-WebColor.pdf

Dark patterns on shopping websites:
https://webtransparency.cs.princeton.edu/dark-patterns/

Create your own fake news:
https://grover.allenai.org/

Archive a web page:
https://archive.is/

English pronunciation:
https://youglish.com/

Light and sounds pets hate:
https://www.cnet.com/news/is-technology-driving-your-pet-insane/

Literal meanings for country names:
http://tiny.cc/countrynames

WiFi networks found:
https://wigle.net/

Preconfigured virtual Linux for investigations:
https://inteltechniques.com/buscador/

Free virtual private mobile number:
http://freesmscode.com

Price optimization game:
https://priceoptimization.ai/

Introduction to SQL for Data Scientists:
http://downloads.bensresearch.com/SQL.pdf

40 years of New York City photos:
http://mattweberphotos.com/

H.P. Lovecraft complete works:
http://arkhamarchivist.com/free-complete-lovecraft-ebook-nook-kindle/

Audubon native plants database:
https://www.audubon.org/native-plants

Visual comparison shopping:
http://www.findsimilar.com/

Feminist internet:
https://f-xa.co/

Best way to whisk:
http://digg.com/video/the-best-whisking-method-explained

Follow politicians:
https://app.politiscope.io/

Go for a walk:
https://walk.cafe/ 

Lists made social:
https://list.ly/

Image to text and translate:
http://projectnaptha.com/

3D human body:
https://human.biodigital.com/login/create

Learn geography:
https://lizardpoint.com/

New startups:
https://betalist.com/

Privacy-focused office tools:
https://cryptpad.fr/

Publish your research:
https://www.qeios.com/

What did Alexa hear and store?
http://www.amazon.com/alexaprivacy

Selfie teleprompter:
https://smartphones.gadgethacks.com/how-to/turn-your-phone-into-teleprompter-record-selfie-videos-without-breaking-eye-contact-0196702/

Soviet's code machine, better than Enigma:
https://foreignpolicy.com/2019/04/27/the-soviets-unbreakable-code-fialka-encryption-espionage-russia-kgb-spy/

A Bittorrent client:
https://www.qbittorrent.org/download.php

Whats on your PC?
https://www.ccleaner.com/speccy/download

Find hidden cameras:
https://www.howtogeek.com/411095/how-to-detect-hidden-surveillance-cameras-with-your-phone/

Inside the mind of a hacker:
http://tiny.cc/insidehackers

Free content distribution network:
http://coralcdn.org/

How a transmission works:
https://youtu.be/JOLtS4VUcvQ

Gravity points:
https://codepen.io/akm2/full/rHIsa

Classified ad exchanges:
http://www.dontevenreply.com/

Fake SD/USB tester:
https://www.majorgeeks.com/files/details/fakeflashtest.html

Cheap flights from where you are:
https://greatescape.co/

13.8 billion years for free:
https://school.bighistoryproject.com/bhplive

Ancient Rome, then and now:
https://www.boredpanda.com/before-after-roman-buildings-structures/

Ransomware rescue manual:
https://www.wired.com/wp-content/uploads/2016/03/RansomwareManual-1.pdf

Guided meditations:
https://www.tarabrach.com/guided-meditations/

Phish in a barrel:
https://duo.com/assets/ebooks/phish-in-a-barrel.pdf

Danish destress:
http://theconversation.com/a-danish-word-the-world-needs-to-combat-stress-pyt-112216

Talk about mental illness: 
https://seizetheawkward.org/

MIT Machine Learning textbook:
https://www.deeplearningbook.org/

Screen capture and file sharing:
https://getsharex.com/

8 hours of Star Trek Voyager crew quarters sounds:
https://www.youtube.com/watch?v=wHxBp4zPTBQ

8 hours of Star Trek TNG cargo bay sounds:
https://www.youtube.com/watch?v=5VNhGe3wOOE

8 hours of Star Trek TNG Engineering sounds:
https://www.youtube.com/watch?v=MNBA2U-L8dc

8 hours of Star Trek TNG Ten Forward sounds:
https://www.youtube.com/watch?v=4tzoIYyAhFY

8 hours of Star Trek TNG bridge sounds:
https://www.youtube.com/watch?v=UKBvaOLDem0

Mars' weather:
https://mars.nasa.gov/insight/weather/

Interactive programming environment:
https://repl.it

Computer generated cats:
https://thiscatdoesnotexist.com/

Computer generated faces:
https://thispersondoesnotexist.com/

Gene editing at home:
http://www.the-odin.com/

Chrome password protection tool:
https://security.googleblog.com/2019/02/protect-your-accounts-from-data.html

Live stream video:
https://www.youtube.com/live_dashboard_splash

File virus scanner:
https://virusscan.jotti.org/en

Snap an image of a webpage:
https://screenshot.guru/

Ultra-condensed books:
http://www.rinkworks.com/bookaminute/classics.shtml

Plane deformations:
https://mrdoob.com/#/124/plane_deformations

Medieval medicine:
http://theconversation.com/medieval-medical-books-could-hold-the-recipe-for-new-antibiotics-74490

Patience is a virtue:
http://www.patience-is-a-virtue.org/

Random street:
http://www.mapcrunch.com/

Rock, Paper, Scissors:
https://www.rock-paper-scissors-game.com/

Found notes:
http://foundmagazine.com/

Awkward photos:
https://awkwardfamilyphotos.com/

Stuck drawer simulator game:
https://games.increpare.com/Schubladesimulator/

Perfectly timed photos:
http://perfectlytimedphotos.com

Kim Jong-Il looks at things:
https://kimjongillookingatthings.tumblr.com/

Thinking about your partner can lower blood pressure:
https://uanews.arizona.edu/story/having-partner-present-or-mind-may-keep-blood-pressure-down

Learn to program for free:
https://www.sololearn.com/

Where can I watch a movie?
https://www.justwatch.com/us

Private, encrypted file sharing:
https://send.firefox.com/

Make a bootable USB:
https://rufus.ie/

Amazon giveaways and discounts:
https://www.amazon.com/ga/giveaways?pageId=1

Google's last result:
https://feelingunlucky.today/

Unroll toilet paper with your mouse wheel:
http://papertoilet.com/

Why time flies faster as you age:
https://qz.com/1516804/physics-explains-why-time-passes-faster-as-you-age/

Cut/paste emojis:
https://www.emojicopy.com/

Find a tutorial:
https://2uts.com/

Free Javascript course:
https://watchandcode.com/p/practical-javascript

Private search engine:
https://news.google.com/newspapers

Newspaper archive:
https://news.google.com/newspapers

Point and kill for Windows:
https://bitbucket.org/sta-ger/win-xkill/downloads/

Color wheel:
https://color.adobe.com/create/color-wheel/

Compress PDF files:
https://smallpdf.com/compress-pdf

Old SD memory card formatter:
https://www.sdcard.org/downloads/formatter_4/

Full moon:
https://www.reddit.com/r/space/comments/a6kzqr/the_full_rotation_of_the_moon_as_seen_by_nasas/

Inspriation:
https://ineedaprompt.com/

Elements through the centuries
https://www.reddit.com/r/educationalgifs/comments/a6lr6n/300_years_of_element_discovery/

Virtual credit cards:
https://privacy.com/

When was a webpage posted?
http://carbondate.cs.odu.edu/

Old masters' Easter eggs:
http://www.artspace.com/magazine/art_101/conspiracy-theory-for-art-nerds-find-the-eerie-easter-eggs-hidden-in-6-old-master-paintings

Raising self-reliant children:
http://www.freerangekids.com/

DIY home decor:
https://www.simphome.com/

Yet more free movies:
https://www.roku.com/whats-on/the-roku-channel

Even more free movies and TV:
https://www.snagfilms.com

More free movies and TV:
http://popcornflix.com

Free movies and TV:
https://www.sonycrackle.com

Reduce image size:
https://squoosh.app/

Coding quizes:
https://coderbyte.com/quiz

Convert web app to desktop app:
https://applicationize.me/now

Researcher network:
https://www.researchgate.net/

Learn to hack:
https://www.hacksplaining.com/

2050 Weather:
https://www.vox.com/a/weather-climate-change-us-cities-global-warming

Burn OSs to USB sticks or SD cards:
https://www.balena.io/etcher/

Automated vehicle safety:
https://www.rand.org/content/dam/rand/pubs/research_reports/RR2600/RR2662/RAND_RR2662.pdf

Search words by when first used:
https://www.merriam-webster.com/time-traveler

Windows Explorer alternative:
http://multicommander.com/

Company contact info:
https://www.elliott.org/company-contacts/

Take flight:
https://www.foldnfly.com/

Interesting news:
https://www.tickld.com/

Programming finishing school:
https://thoughtbot.com/upcase

Free undelete for Windows 10:
https://www.easeus.com/data-recovery-solution/free-undelete-software-windows-10.html

Screaming goat piano:
http://www.screaminggoatpiano.com/

Dividing circles:
http://www.koalastothemax.com/

A sad trombone:
https://www.anothersadtrombone.com/

Pull my nose:
http://vectorpark.com/head/

Meteorological info:
https://www.ventusky.com/

Create a website:
https://www.jimdo.com/

Control someone else's electronics:
http://www.drivemeinsane.com/

Free credit freeze:
https://www.marketwatch.com/story/freezing-your-credit-is-now-free-2018-09-21

Java tutorial videos:
https://www.youtube.com/watch?v=TBWX97e1E9g&list=PLE7E8B7F4856C9B19

Open source video editor:
https://kdenlive.org/en/features/

Any positive number is sum of three (or less) palindromes
http://www.rnta.eu/cgi-bin/three_palindromes/pal3.py

Open source painting tool:
https://krita.org/en/features/highlights/

Image viewer:
https://nomacs.org/

Snapzu web posts:
https://snapzu.com/

Visual microphone:
https://www.youtube.com/watch?v=npNYP2vzaPo

Where can you park you spaceship?
https://parkmyspaceship.com

Clone your disk in the clouds:
https://rclone.org/

Make your PC into a hotspot:
http://www.mypublicwifi.com

Vedic math books:
http://www.vedicmaths.org/resources/books/free#book

Journey to the center of the earth:
http://www.bbc.com/future/bespoke/story/20150306-journey-to-the-centre-of-earth/index.html

Mount Rushmore's Hall of Records:
https://www.nps.gov/media/photo/gallery.htm?id=F51F46AD-155D-4519-3E23A791A6417362

Group Theory coloring book:
http://www.coloring-book.co/

Identify fake photos:
https://www.getsurfsafe.com/

Zoom quilt:
http://zoomquilt.org/

Nothing for something:
https://payfornothing.club/

Exercise for muscle groups:
https://musclewiki.org/

Odd Internet photos:
http://internethistory.tumblr.com/

Google Feud game:
http://www.googlefeud.com/

Weird or confusing:
https://weirdorconfusing.com/

The earth over time:
http://dinosaurpictures.org/ancient-earth

Math tools:
https://onlinemathtools.com/

Help research:
https://www.zooniverse.org/

Everyday sayings:
https://www.stylist.co.uk/books/everyday-sayings-explained/124076

Peer-to-peer file transfer:
https://file.pizza/

Machine Learning 101:  http://tiny.cc/ML101

More free photos:
https://www.pexels.com/

Free stock photos:
http://makerbook.net/photography

3D cat portraits:
https://www.boredpanda.com/realistic-cat-portraits-needle-felting-wakuneco/

Find a podcast:
http://www.podcasts.com

Free Artificial Intelligence course:
https://www.elementsofai.com/

Free screen design tool:
https://www.invisionapp.com/

HTML5 interface visual authoring:
http://maqetta.org/

Forever falling:
http://www.fallingfalling.com/

Make some music:
https://onlinesequencer.net/

What others have achieved:
https://www.agegeek.com/

HTML cheat sheet:
http://hostingfacts.com/html-cheat-sheet

Programming community:
http://www.devshed.com/

Find keyword ideas:
https://neilpatel.com/ubersuggest/

Scientific calculator and more:
http://www.kalkules.com/

Free cyber security training:
https://www.cybrary.it/

Voice recognition in Chrome browser:
https://dictation.io/

Free web-based PDF editor:
https://www.pdfescape.com/

Drag and drop Android and iOS apps:
https://thunkable.com/#/

Help a sight-impaired people:
https://www.bemyeyes.com/

Temporary or limited credit card numbers:
https://privacy.com/

Automating Chrome:
https://www.maketecheasier.com/extensions-automating-repetitive-browsing-tasks/

Printing on wood:
https://www.instructables.com/id/5-Ways-to-Print-on-Wood/

Create a digital signature:
https://www.mylivesignature.com/