There was one I used to play on an Apple clone that was really good. You faced fighters that got bigger and better, so of like Mike Tyson. The one I remember the most was the first guy who would rabbit punch you and he lifted his feet off the mat when he did it. Though it really was not a good thing for my boxer it was funny to watch!
The original Knockout Kings for PlayStation. I remember thinking that this is the first time the characters moved like real boxers, punched like real boxers. Then I beat the game and see they used motion capture of real boxers. Cool stuff.
My favorite is "Mike Tyson's Punch Out!!!" as it was the only boxing game my brother or I had. I have a lot of good memories from the two of us taking turns playing it, and of playing Zork on my computer while he practiced MTPO endlessly for the first NES championship — we did that so much that the MTPO soundtrack runs in my head whenever I think of Zork 1 and vice-versa.