Links I just find to be useful in general or don't fit into a category.
- Learn X in Y Minutes - Like a cheatsheet of cheatsheets for various languages.
- Build Your Own X - Tons of links to resources on how to build various types of things.
- roadmap.sh - Basically roadmaps of "what should you learn" to become good at the specified thing.
- Addy Codes Toolkit - Repository of web development tools/links/etc.
- Freecodecamp Youtube - It's hard not to find a good course on just about any programming subject.
- HTML/CSS
- JavaScript
- Web Development - Bringing HTML, CSS, and JavaScript together for both frontend and backend.