I'm unaware of any and another about free jazz is that defining it is difficult as it was never a distinct genre.
It is hard to explain it because it cannot be define and was never really a genre of music
I really love jazz as a musical genre.  Do you like jazz? I'm not but do you like free jazz? It got made around the 1950s to the 60s. I have never heard of free jazz.  What are some of its most popular artists?
As its name implies, free jazz cannot be defined more than loosely, as many musicians draw on free jazz concepts and idioms, and it was never completely distinct as a genre.