guys who always showed up and never underestimated their opponents. They didn't necessarily win 100% of their fights but guys who were nonetheless consummate professions. Hopkins and Usyk come to mind.
Povetkin Quarry Come to mind for contenders. They had long successful careers because they were always ready at every stage of their career.
Mayweather, Joe Frazier, Usyk. I'd probably give Usyk first place actually. He is always 100% on it, his concentration levels and dedication on and off the ring is unbelievable.