Resources for various computer science-y things.
https://teachyourselfcs.com/: Self explanatory.
free-for.dev: a list of various free-tiers of services for developers.
Regexr: Playground for learning the rules of regular expressions.
Git Internals - How Git Works - Fear Not The SHA!: Great explanation of what git "physically" is on disk.
Git Internals - PDF: Incredible explanation of what git is and what each command does.
Learn Git Branching: Interactive visualizer/tutorial with challenges.
Visualizing Git: General git playground & visualizer.
gitignore.io: Search for various gitignore templates based on the project or environment.
Openvim: Interactive tutorial for Vim
Vim Genius: Tests your knowledge of Vim keybindings.
Tips and Tricks for .NET Debugging in Visual Studio: Awesome explanation of some lesser-known VS 2019 features.