10. Luke Gallows
Luke Gallows and Karl Anderson are currently creating quite a stir as WWE's newest tag team, but they've already got years of experience under their belt in New Japan Pro Wrestling. There, the tandem became three-time IWGP Tag Team Champions and essential members of Bullet Club.
Gallows was (and is) perfectly serviceable as a fairly agile big man with some good-looking punches, but sticking him with Anderson on a permanent basis overshadowed just how good "Machine Gun" was. On the rare occasions when Anderson got to wrestle singles matches (such as in the G1 Climax, or when receiving a shot at the IWGP Heavyweight or Intercontinental Titles), he was a compelling worker capable of mixing it up with New Japan's best. Were it not for the fact that the company already had one of the world's best workers in AJ Styles, Anderson would have made a perfectly acceptable foreign ace.
Anderson hasn't really gotten to show his skills thus far in WWE, and while there is money in a run with Gallows, it would be a shame if he never gets to grow beyond the pairing.