Daniel Bryan
Bryan had to relinquish titles different times in his career. He had a nasty neck injury which gave him trouble for his entire career. After Wrestlemania 30, he due to legit concussions he had to relinquish the WWE World Heavyweight championship. He returned for a couple of times but had to relinquish the Intercontinental title twice in 2014 and 2015. Then came the saddest day when he decided to take retirement, earlier this year.