#5 Luke Harper
Luke Harper has not been seen on TV since losing the SmackDown Tag Team Championships to the New Day in August of 2018, having been out with a wrist injury.
Luke Harper is a former member of the Wyatt Family, and has won the SmackDown Tag Team Championship twice, once with the Wyatt Family, and once with Erick Rowan as the Bludgeon Brothers. He even won the Intercontinental Championship once in 2014 from Dolph Ziggler, only to lose it a few short weeks later.
Luke Harper was over in early 2017, splitting from the Wyatt Family and turning face, however, WWE failed to capitalize on Harper's momentum and decided to not insert him into the WWE Championship match at Wrestlemania 33, which could have saved what was a rather boring match.
Recently, WWE published a video on their YouTube channel listing main roster superstars who should be in NXT, which included Luke Harper. Luke Harper never received his time to truly shine as a singles competitor, whether that be in the main roster or NXT.
Having already challenged Ricochet for the NXT North American Championship at a live event in his hometown of Buffalo, New York, a move to NXT to challenge for the NXT North American Championship during the 2019 Superstar Shakeup could be what Harper needs to get his career back on the right track.