One compilation of the top ten knockouts of all time is here. Some of them are fuzzy and old--that's what you get for "all time." But many would say Mike Tyson's top knockouts alone have more ferocity in them than most other fighters combined, including the top ten. That's not to say Tyson was the greatest--that title belongs resolutely to another pugilist.
But for ferocity, speed of attack, pure aggression--and let's mention the frequent mismatch of opponent--Tyson makes a case for knockout king.
[Try The All-NEW Amazon Echo Dot]