15. Al Iaquinta
Iaquinta fought in the UFC lightweight division for many years. The straight-talking New Yorker famously took on Khabib Nurmagamedov at short notice. He didn’t win that title fight but he earned admirers because he took the champion to a decision. However, Iaquinta had problems with the promotion because they underpaid him. He’s one of many fighters who had contract holdouts (via The Score).

In 2016, he withdrew from UFC 205 because the promotion didn’t pay him enough. Iaquinta claimed that the cost of injuries and a training camp didn’t justify fighting. He returned to action but was away from the cage for over a year. It’s a shame but it’s a reality that the UFC underpays its fighters compared to other sports. Iaquinta did the right thing for his career.