Scan the all-time rankings of mixed martial artists by any number of measures -- whether looking at total days reigning as a UFC champion, FightMatrix's computer rankings or ESPN's ranking of the top 10 fighters of the 21st century from two years ago -- and one name you won't find is arguably the biggest name in the sport: Conor McGregor.

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Watch Kamaru Usman put an end to his three-fight losing skid with a win over Joaquin Buckley ahead of his return at Saturday's UFC OKC.

The UFC is back in Abu Dhabi on Saturday, with a light heavyweight main event between Magomed Ankalaev and Bogdan Guskov at UFC Fight Night. Of course, every former titleholder's goal is to return to a championship fight.