10. Conor McGregor
You can often hear two extremes about this MMA star. His loyal supporters call Conor the best fighter of his generation, while detractors suggest that he is grossly overrated. As is often the case, the truth lies somewhere in between. McGregor defeated many famous mixed martial arts fighters, which brought him worldwide fame. Among his outstanding achievements are victories over Dennis Seaver, Diego Brandão and José Aldo. McGregor knocked out the latter in 13 seconds, which was the fastest UFC title fight in history. The Irish superstar also made history as the first MMA fighter to compete in two different weight divisions and defend his title in each for over a year in a row.