Oh My God. This is next to impossible, SOOOOOOO many great fighters are underrated or unheard of today for whatever reason. So I'll just list a couple.

One of my favorite boxers ever is Ike Williams. In my opinion, he is one of the greatest lightweights of all time but you'd be hard pressed to find him on a lot of greatest lightweight list. Truly overlooked imo, but man he was such an exciting fighter. One of the more tremendous combination punchers ever.