#1 Turned down WWE: Sting

When WCW folded in March 2001, many fans were intrigued to see which stars would appear in the World Wrestling Federation. Almost everyone did, as DDP, Booker T, Scott Steiner, Goldberg, and the NWO all joined the McMahon-led promotion, though one name was noticeably absent.
Sting.
According to the man himself, Sting was sent various requests to join WWE over the years, but always turned them down. In a 2011 interview, the Stinger said how the track record of other WCW stars made him cautious about ever joining WWE.
Ultimately though, Sting did sign, and made his shocking debut at Survivor Series 2014. Attacking Triple H (who had defeated many WCW stars during his 2003 World Title reign), Sting would have a handful of WWE matches before his retirement in 2016.