Definitely Muhammad Ali. Even though he leaned back, had his hands down, and rarely threw body punches, Ali was one of the greatest fighters of all time. He made wrong right, which not many fighters can do.
Would Jeffries bending almost in half during fights fall into the unconventional ? Slapsie Maxie Max Bear Jersey Joe Walcott. Keep well.
Fury, very tall, but fast in footwork and he can go southpaw. Can be serious or show up in a batman costume for press conferences.
Sergio Martinez' hands-down guard is one of the most unconventionally effective things seen recently in boxing.
Roy Jones and prince are the obvious choices that'll come up to mind instantly. From today's perspective I'd add Deontay Wilder to the list. He's got one of the most impressive title defense/KO lists in HW boxing history by just standing still and waiting for one opportunity to launch a straight right in every fight.
Muhammad Ali Roy Jones Jr Manny Pacquiao Jersey Joe Walcott Naseem Hamed Vitali Klitschko Sergio Martinez Joe Calzaghe Michael Spinks
Most the obvious ones have been said... So I'll throw in Koichi Wajima, anyone who throws the damn Frog Punch needs to be mentioned! Carlos Maussa did pretty well Vic Darchinyan was rather unconventional Also going forward Fundora needs a mention, he's about as unconventional as they come