Re:Ask HN: How Can I Learn Music Theory?
by zozbot234 on Wednesday December 18, 2019 @10:52AM
(#21826080)
OMT is a good resource, but it seems to have gone unmaintained https://github.com/openmusictheory/openmusictheory.github.io Someone should either get in touch with the authors or fork the project.
EDIT: I also really like this YouTube series: https://www.youtube.com/watch?v=mdEcLQ_RQPY&t=74s&ab_channel.... The videos are relatively short, so if you like fast-paced high-density videos then you should enjoy this format.