This community is primarily structured around the sort of subjects you would see in an academic setting, but learning skills is absolutely within the scope of this community. If you have any, please consider commenting with free resources and advice for things like playing an instrument, learning a language, woodworking, etc.
https://github.com/sjpiper145/MakerSkillTree
Very interesting way to present things and track progress.
Existing communities are also very useful. For example:
!languagelearning@lemmy.world
!languagelearning@sopuli.xyz
For woodworking with hand tools:
You can’t go wrong with Paul Sellers.
For printed materials, there is Christopher Schwarz and his Lost Art Press. Obviously, the books aren’t free, but his first in the “Anarchist” series transformed my approach to my hobbies, not just woodworking.
The YouTube channel Frank’s Workbench has a lot of great stuff, too.
Learn various coding languages with Codecademy. Follow career or skill paths, or jump around to whatever course you need. https://www.codecademy.com/
Free with paid certificate options. I’ve personally found the free content to be enough, supplemented with YouTube videos or coding project ideas from elsewhere around the web.
Open Source Society University https://github.com/ossu/