#6 The Rock 'n' Roll Express
This one sounds weird to say but yes, 20 years after they formed, The Rock 'n' Roll Express, Robert Gibson and Ricky Morton joined TNA in early 2003.
The Rock 'n' Roll Express are one of the all time greatest tag teams, having wrestled for WWE, WCW, ECW, NWA, AWA, and more than 50 other promotions over the years, and have held countless Tag Team Championships throughout them all. They were inducted into the WWE Hall of Fame in 2017.
The Rock 'n' Roll Express joined TNA in early 2003, and although initially debuting as faces, they quickly turned heel and joined up with Vince Russo's Sports Entertainment X-treme faction. During this time they mostly feuded with top TNA tag team America's Most Wanted. They left shortly after. They returned to Impact Wrestling for a cameo appearance in December 2016 during the Tag Team Apocalypto on Total Nonstop Deletion.