How about some of these (no particular order) over the past

Marvin Hagler
Julio Cesar Chavez
Muhammad Ali
Dwight Muhammad Qawi
George Foreman
Larry Holmes
Mustapha Hamsho
George Chuvalo
Khosai Galaxy
Jake La Motta
Rocky Marciano
Carlos Monzon
Kid Gavilan

That's enough concrete there to build a dam!