I recommend this a lot if you want to design some visual aid. Also comes with desktop versions though I don't really recommend it as it's mostly the same except you run it in the desktop.
Freebies Hunt is a programmer-oriented and a personal resource list gathered by @foo-dogsquared after having a stroke with open content enthusiasm. This'll help you in finding quality free (and open source) resources to get started doing on your projects (or learnings).
Freebies Hunt is also an open source website which you can see the source code for it right here. Of course, feedbacks and contributions are welcome! 🤗
Got API?
If you are looking for an API of this site (for some reason) to get its data, you're in luck! It's available as an npm package. You could also see the source code of it in this remote repo.
Personal comment:
My go-to color scheme generator.