Not curated but well organized listing of MOOCs, including marketing, design, etc: <a href="https://www.coursebuffet.com/areas" rel="nofollow">https://www.coursebuffet.com/areas</a>
There are a couple of things on this list that claim to be free, but when you click through aren't. One example is the 10 Days to Better Design course that is actually $10.