Simply the best of those crazy and desperate enough to be asked and willing to compete.
Tank Abbott was one of my favorites from that time period as well as Mark Coleman and Vitor Belfort at only 19 years old! I remember how psyched up I was for the fight between the two men that would determine the first UFC Champion ( as opposed to being the champion of a particular tournament only). It was Mark Coleman vs. Dan Severn in a fairly short but exciting fight. Coleman used his neck crank to win. Even though I liked the idea of them establishing an actual UFC Champion and Coleman and Severn were both elite level wrestlers and certainly among the best of their time, I loved watching the tournaments as well. To win a tournament you had to win 3 fights all in the same night! The prize was only $50,000 so it attracted guys who genuinely liked to fight and who were nothing like some of the prima donnas of today. Some of the fighters from the tournament days probably would have been willing to fight in the tournaments for free. Just the opportunity to get in some good fights and test themselves against other martial artists or Olympic level wrestlers and being able to kick someone's ass without going to jail would have been payment enough for some of them. The men from the NHB days really were cut from a different cloth than today's "sport fighters."