The ones that scream at me are Alex emelianeko, dude was fedor but bigger. legit had goat potential but chose to pursue the art of being human filth...
BJ Penn is another one, don't get me wrong, he achieved a fuck ton but I feel like he got cucked out of that GSP first fight which would have maybe catalyzed him to remain more motivated and not just fight for the quick buck.
Cain Velasquez, Nick Diaz, and Tony...All of them were held back from different variables but nonetheless none of them were able to reach the heights of mma that they were capable of.