Sanchez, Pedroza, Arguello, Saldivar, Canto, Harada, Rudkin, Pep, Saad, Ohba, Marcel and Buchanan were all monsters in the championship rounds who got either got stronger as the late rounds went on and kept ratcheting up their output round by round or/and maintained perpetual movement and fought at a pace moving laterally and backwards punching on the move for the full 15. I still think that Buchanan is underrated in this regard because of his short peak and style. He was immensely strong despite not being a huge puncher and was still up on his toes triple jabbing, jigging and maintaining cyborg like punch stats in the 15th grinding the likes of Laguna, Watt and Navarro down. The way he was able to outgrit Laguna in the heat in Puerto Rico was immense. Even when getting knocked about Duran he didn't look tired or discouraged, nor when he couldnt see in the late rounds against Ishimatsu and was being hit at will like a bobble head doll.
Joe Calzaghe, Aaron Pryor, Vito Antuofermo, Anthony Crolla, Sergio Martinez, Ricky Burns and Steve Collins spring to mind.
Guys that went 50-60 rounds back in the old days...can't believe anyone could fight that long. No mouthpieces, probably no cup protectors, small gloves.
Jem Carney is a real stand out from back then. A freakish ability to seemingly get stronger after fighting an insane duration
Surprised no one has mentioned Sugar Ray Leonard. The man could summon reserves of energy from nowhere. See: Leonard v Hearns rounds nine on…
Jeff Fenech was like a human windmill, he fought at a frantic pace and kept that pace going from start to finish. Daniel Zaragoza is another fighter that never seemed to tire.
The Marcos Geraldo fight comes to mind. Geraldo constantly pushing forward full steam like a mad man intent of landing something anything. SRL evades jabs and pounds him every time round after round effortlessly. Never even looks tired dispute never getting to rest for 5 seconds the entire fight.