#10 Gallows and Anderson
One team that WWE seemed to sign simply to block them from going elsewhere was the duo of Gallows and Anderson. They were a big part of the Bullet Club before the group's schism in 2018, but WWE probably felt taking them away from NJPW would put a huge dent in the company.
While it did to an extent, WWE hasn't done much with the duo. They were by the side of Finn Balor and AJ Styles briefly, but waded back into tag team obscurity soon thereafter.
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They did have a run with the Raw Tag Team titles, but after that, they've mainly been a team in the rotation of teams that either aren't featured or dusted off monthly for a random title shot.
Their act does work better as a part of a faction, but WWE has dropped the ball with Gallows and Anderson and the tag team division in general. Who knows how close the duo is or isn't with the Young Bucks because most of the Elite was formed after they left NJPW. They would probably have more loyalty to NJPW or ROH.
The simple fact remains that like The Revival, Gallows and Anderson are another good tag team that has been wasted on Raw and Smackdown.