Conor McGregor

Conor McGregor's press conference at UFC 194—'I'd like to take this chance to apologize... to absolutely nobody'—remains the single greatest promotional moment in UFC history. However, his mouth peaked around 2016 and his fighting followed suit. Since beating Eddie Alvarez for the double champ status, he has gone 1-3 in MMA and 0-1 in boxing. Despite this, he remains the biggest PPV draw in combat sports, selling 6.5 million buys for Mayweather alone—far more than the average fighter. This brand outlived his performance, and his 25% win rate in recent fights is worse than Terrell Owens' 62% career catch rate.