10. Alberto Del Rio
https://www.youtube.com/watch?v=zHG6LjtsxJM Alberto Del Rio was legitimately one of the toughest men to ever step foot in the WWE locker room. He would have in fact been an Olympic wrestler when he was younger, but Mexico couldn't afford to fund a wrestling team. Instead he ended up in the family business, pro wrestling. But he also took on a range of MMA fights, competing mostly in Japan as Dos Caras Jnr. His record was mixed, finishing up in 2010 as nine wins and five losses. He fought for PRIDE, including a high profile fight with MMA legend Mirko Cro Cop. But an offer from the UFC was never forthcoming, hence his decision to quit MMA and join WWE in 2010. When he left WWE in 2014, there were rumours that both UFC and Bellator were looking to sign him. Bellator would certainly be a good fit, and that deal could still happen.