That rules out guys like Freitas and McClellan, who both entered the ring 3 divisions bigger than the weigh-in. Who stands out for you as a guy with KO power who wasn't milking the weigh-in rules?
Apart from heavyweights, of course, just to back to the same-day weigh-in days: Pipino Cuevas Sandy Saddler Archie Moore Julian Jackson (maybe by the time he was fighting at middleweight we were beginning to have day-before weigh-in and weight bullies like Gerald McClellan were starting to become a thing) Michael Spinks Little Red Lopez Ray Robinson Etc Etc