Who are some fighters, past or present, who have fought and beat everyone in their weight class? I know Wlad and Ward have.
Tszyu, Hopkins, Hagler, Tyson, Lewis, RJJ at Light Heavyweight, Holyfield, Marciano, Louis and many more.
Lots of fighters - Lewis, Tyson, Hagler, Hopkins, holyfield, Calzaghe, Wlad, Ward, Haye at cruiserweight? Spring straight to mind. I'm sure there are loads at the lower weights in recent memory - Gamboa didn't beat juanma but didn't really need to.
Joe Louis is the king here. Only fighters he never beat that he fought were Ezzard and Marciano, and that is easy to dismiss when you factor in Louis' age at the times of those bouts and the year+ official retirement. --- Recently, Pongsaklek Wonjongkam did a number on the whole Flyweight division for many years. Fought them all. --- Carlos Monzon and Ray Robinson at MW deserve big shout outs here too.