#2 Kevin Owens and Sami Zayn

Owens and Zayn were competing as a tag team on both Raw and Smackdown, before injuries to both superstars had led to them being taken off WWE television. Despite the fact that Kevin Owens had turned face during his injury angle on October 8th, 2018 on Raw, WWE could easily reunite Owens with Zayn whether it's as faces or heels to implement them into the tag team division.
When the duo was regularly teaming up, it was a pairing that worked due to the fact that the two men are best friends in real life. It allowed us to see Zayn's personality that he desperately needed to establish himself in the WWE, and it also gave Owens something to do after having a personal rivalry with Shane McMahon.
The duo was rarely used in the tag team division as a whole, as they were mostly utilized to build up the main event scene, teaming up against the likes of Shinsuke Nakamura and AJ Styles whilst they were involved in a rivalry. Seeing Owens and Zayn mix it up with teams like Gable and Roode as well as AOP would be very interesting to watch as there are potential for good matches.
Most importantly, if the duo were to return as heels, then they would be the perfect team to instigate a potential heel turn for Bobby Roode. Owens and Zayn are Canadian superstars just like Roode is, and they could claim that Gable is holding Roode back from being truly glorious.
But even if they did return together as babyfaces, there would be no denying that the WWE Universe would love them as they are very popular superstars today in the wrestling world.