I’ll start by plugging Harvard’s free courses catalog as well as Udemy
Edit: Gonna add 2 more I remembered-
Blender - I wish I had more time to learn it, but I did start the infamous “Donut Tutorial” once!
Watch Cartoons Online - Lots of good older stuff!
I kinda forgot Project Gutenberg is a thing. I read a bunch of stuff on there in the late 90s/early 2000s, Arabian Nights, Paradise Lost, etc.