If you're talking single shots Lewis hit Klitschko with an absolute peach during their fight, how Vitali stood up to it I'll never know
Benvenuti had a brilliant lead right uppercut. Arguello to the body. Azumah Nelson Kalambay had maybe the best counter uppercuts from the outside i've ever seen, a punch many fighters can't even attempt for fear of being badly countered, yet he seemed able to throw it from multiple angles, in almost any situation.It was a bit of a weakness as well as a strength though, as he often waited for the ideal countering chance to use it when it may have been more appropriate to just let the straight right go.
That's basically all he uses. Like Foreman, he seems to throw most of his punches from low to high and in an upper cut arc. Tyson did that a lot too, where as Lewis' upper cut was more conventional, although he wasn't beyond holding the head of a fighter when he delivered it. (ie Grant) that was brutal.
Just some names that immediately came to mind: Mike Tyson Roberto Duran Jack Johnson(one of the few clean shots you can see consistently in those old films) Larry Holmes George Foreman Also Riddick Bowe. Razor Rudduck(though that was more of a hook/uppercut hybrid). Mike McCallum(to the body).
The fellow who's surname you have in your username threw a mean uppercut or two in his time . Walcott had a sidewinder on him too when he used it ie. the Charles ko. As an aside, I was re-watching Lewis-Mavrovic the other day and I'd forgotten just how many good full-blown uppercuts and overhand rights Mavrovic swallowed that night. Hard man he was.