Omniversity

If your connected education is available. It's focus that is often in short supply: https://www.edx.org/

It's just a share fest, but here's my first recommendation. https://www.p2pu.org/en/
I love open source nearly as mush as I love peer to peer learning as a practice. Give a man a fish and you fed him for a day, but if you teach a man to fish you feed him for life. (anon)