The whole UFC roster with Fedor. Not that I think Fedor was ever afraid to fight anyone, but he let his team duck him out of top competition after Pride. There was no reason he should have wound up in Affliction and Strikeforce after Pride was dissolved into the UFC, when the UFC was offering him the money he was worth.
First M1 said they didn't like the exclusivity terms, so the UFC actually negotiated to let him compete in Sambo tournaments if he wanted to while under UFC contract. He still declined.
Instead of seeing him fight Randy, Brock and Cain back when they were all at the top of the HW mountain, he fought UFC washouts in Affliction and then even lessor comp in Rogers when he first wound up in Strikeforce. He wasted the last of his prime years fighting lessor comp, and at the time it seemed like his management were just ducking the UFC.
For fans of MMA back in 06 - 10, this was the most disappointing game of duck going on in the sport.