I was going to say it's hard to find examples where there isn't one who stands out as by far the best talent, and the others are more associated with them, so the Marquez and Klitschko brothers almost stood alone in modern times. I hadn't thought of the Spinks though, that's a good shout as Cory was an excellent boxer in his day. Mayweathers are also hard to beat in that sense, Roger in his own right was a champion and top level fighter for a long time, even predator was clearly talented. Guys like Matthew Hatton or Jose Cotto would have probably never gotten relevant fights if it weren't for the family connection, even though they gave the odd good account of themselves.

Early doors of course, but the Charlos are a rarity already. I thought Jermell was the better one for a time, but now it's looking like the other is, either way both class.