#4. AJ Styles
If someone told us in 2010 that not only would AJ Styles sign with WWE, but become a major player in the company, we would have probably laughed it off. A TNA/IMPACT Original, Styles started out in the business with WCW when the company was at its deathbed. In 2002, he would sign with TNA and quickly become one of its cornerstones. He had excellent matches against the likes of Kurt Angle, Samoa Joe, Sting, Jeff Hardy, and Jeff Jarett during his decade-plus run in the company.
Despite IMPACT's financial woes and their mistreatment of homegrown talents, the Georgia-native remained loyal to the company for the longest time. But, in 2014, he finally had enough. After his contract expired, Styles decided against re-signing with the company, as his new deal included a severe pay-cut.
Following his exit from IMPACT, Styles would head to the Land of Rising Sun. As the leader of Bullet Club, 'The Phenomenal One' became the top gaijin star in New Japan and held the IWGP Heavyweight Championship on two occasions.
Styles made his WWE debut at the 2016 Royal Rumble to a raucous response from the crowd and would go on to win the WWE Championship a mere eight months after debuting for the company.
Styles has become a staple of WWE and firmly established himself as a top star in the company. His ability to deliver knockout performances inside the squared circle hasn't diminished as 'The Phenomenal One' has consistently put out some of the best WWE matches in recent memory.