Usyk & Lomachenko and they were in the same team with the same trainer. Mental. when they were in the same tournaments/same bills at the world championships 2011/olympics 2012/ WSB 2013 you just knew they were very special unique talents that were gonna do huge things in the pros.
Canelo, Hes style is very rare in Mexican boxing not only that but by the time he retires he might be the goat of Mexico, like it or not.
First two names I thought of RJJ and Second to Nunn. Talents in the respect, I believe both men had natural abilities (reflexes, trunk agility and hand speed) that were so supreme they trumped any skill. For a time it's enough and both probably didn't even have to train much to look as amazing as they did.
I see actual lists of "once in a lifetime" talents. Isn't the whole thing that there's only a single one in about a 70 year span?