Greatest Pre UFC era fighters

Who were the greatest MMA/NHB fighters of the 80's, 70's, 40's, etc. I'm a noob on pre-UFC stuff and only know of a few guys like the Helio, Rickson, and Kimura. 

I'm just curious if anyone here is knowledgeable enough to put together a top 10 list of greatest martial artists and NHB fighters of the old days. 

Ivan Gomes

Euclides Pereira