Jeremy Siskind's jazz piano courses taught out of Fullerton College.

https://jeremysiskind.com/jazzclass/

This is a bit of a cheat because these courses are not free ($50USD for California residents and around $400 for non-CA residents) but they are so good that I had to mention them.

I am nearing the end of the Level II course and have learned so much stuff. They force you to do so many things that you otherwise would not do. Basically, ever week you have to post a video demonstrating what you learned from the previous week. And the video is in a public discussion forum with the other students so there is this incentive to do an extra good job. And he gives great feedback on your assignments.