1-Anthony Joshua/Francis Ngannou 2-Alexander Povetkin/Dillian Whyte 1 3-Dereck Chisora/Artur Szpilka 4-Deontay Wilder/Dominic Breazeale 5-Fabio Wardley/Frazer Clarke
Itauma McKean has to be up there. McKean is quite durable and yet he didn't stand a chance. Someone mentioned Zhang-Joyce 2, which is an exceptional ko, so i will second that.
Best HW KO in recent years? Whyte V Povetkin for me. Povetkin (although roided up against someone also probably roided up) was getting battered and torn apart, knocked down then out of nowhere came up with literally the most perfect shot out of nowhere, it was literally perfect. If only the event actually had spectators. Wilder V Szplika second IMO, was also beautifully timed, didn't look that powerful but Szpilka was completely flattened by that one. Wardley V Clarke rematch was quite terrifying because you could see the big dent in Clarke's head.
all of these are good shouts. I would add Ajagba vs Howard - maybe not a super high level/high stakes fight, but a great KO