I'm going to have to agree with those who said Matt Hughes. I know it's odd to call a hall of famer underrated. But I don't think that it's his skills that are underrated, but more his place in history. Obviously, being a welterweight, the goalposts are set at GSP, which is a tough bar. But it seems like now and days, every time a welterweight makes has one or two successful title defenses, all of a sudden they're in the conversation for the welterweight GOAT, or people start asking the question "so and so" vs GSP . Hughes had 2 title runs,totaling 1500 days I cant remember exactly but I think 6 or 7 title defenses, and his resume of victories of some of the greatest fighters of that time, and of all time. Rich Franklin is probably second. If it wasn't for Silva he could have ran MW for a long time.