#5 Kevin Owens and Sami Zayn

While a lot of fans would consider this move to be very unlikely, there's a genuine chance that the creative team of WWE coerces Owens and Zayn to think otherwise.
In a recent podcast with Chris Jericho, Sami Zayn discussed his mental state, and beautifully described his life outside of professional wrestling, which he apparently doesn't really miss.
Despite the fact that the company teased their in-ring returns, not giving them the push they deserve would eventually make them feel dejected about the situation, considering how talented they are.
While Kevin Owens has always been a red hot star in the WWE, 2018 was practically one of the worst years of his entire wrestling year, with the Prizefighter literally made to look like a joke by Braun Strowman.
Moreover, Strowman's dominance of Owens didn't really go anywhere, and didn't make the former Universal Champion look like a threat on Monday Night Raw.
Since Vince McMahon hasn't ever appreciated the idea of moving Sami Zayn into a headlining act, there's room for the former NXT Champion to look for life outside of WWE.
Considering the Young Bucks are really good friends with Kevin Owens and Sami Zayn, they could really ignite their love for wrestling again, and coerce them to join the other side of the tracks.
Despite the fact that the move looks unlikely at the moment, if WWE fails to push them with what they deserve, they might eventually look to join forces with All Elite Wrestling.