Tools, interactive, fun
Tools
Test and explain regular expressions
https://www.bashoneliners.com/
https://explainshell.com
https://rosettacode.org
What Unicode character is this ?
Ffmpeg buddy
Download from youtube
Convert PDFs (correctly handles forms and different versions)
Color
http://www.calmar.ws/vim/256-xterm-24bit-rgb-color-chart.html
https://terminal.sexy
http://www.perbang.dk/rgbgradient/
https://www.december.com/html/spec/colorcmykcompact.html\
Visualisations
Space
https://theskylive.com/
http://stars.chromeexperiments.com/
https://www.moonconnection.com/
https://space.jpl.nasa.gov
https://www.fourmilab.ch/earthview/vplanet.html
Maps
https://www.flightradar24.com
https://www.marinetraffic.com
https://www.davidrumsey.com/
http://aqicn.org/map/world/
https://bost.ocks.org/mike/
https://orbis.stanford.edu/
Math and physics
http://507movements.com/
http://falstad.com
https://www.3blue1brown.com/
https://www.geogebra.org/calculator
Weather
Doge weather
Conditional orchestra generates music based on weather
Fun
Puzzles
Morpion Solitaire
A New Angle
Petals Around the Rose
Blue Eyes
Predicting real numbers
Games
Sandspiel - falling sand game
Doge 2048
20 questions
Cruel but fair minesweeper
Generate
Doge meme
AI image of x
Warning signs
Beauty
Creative coding online interactive websites
https://openprocessing.org/
http://sketchpad.cc/
https://www.shadertoy.com/