If we’re only talking about the left hook then I’ll go with Frazier. Not sure how to compare them with any other punch
Frazier started his hook with his weight on the left foot; it ended up on his right foot because he pushed off his left foot and turned his shoulders. Williams started his left hook with the weight on his right foot and whipped his whole body back over his right leg. That is the better punching technique so i vote Williams. Unfortunately he liked to drop his right hand when he whipped his hook.
Williams stopped Terrell. Tommy stopped Ruddock and Carl Williams, Frazier stopped Mathis, Chuvalo, Quarry, Ellis, Machen, I think Joe by far unless we are talking about hitting the heavy bag.