I’d agree regarding Patterson, he also knocked Henry Cooper out with a single shot, funnily enough it was a right hand!
How many fighters did Holy knock out with one shot, the final right that decked Foreman by Ali was more powerful than any shot Holy hit Foreman with.
He didn't KO many with one shot, but he dropped Bowe with one, not may people can say that, as well as Tyson and Douglas (who had a decent chin and was with One punch)
From memory that final Ali punch didn’t seem that hard at all. In fact none of the final punches that landed seemed that particularly hard but Foreman was so exhausted by then that the cumulative effect of them just helped him on the way down The first punch that knocked him backwards and off balance was probably the hardest of the punches that Ali landed at the finish of the fight.
I would say that Schmeling, Holmes and Holyfield impress me the most, in that they were consistently stopping the better fighters of their eras. Styles and other factors might have played a role in this, and there is no doubt that all of these guys could really crack when they wanted to. If you put a gun to my head, then I would have it something like: 1. Holyfield 2. Schmeling 3. Holmes 4. Walcott 5. Johnson 6. Patterson