#2 The Club (Finn Balor, Karl Anderson, and Luke Gallows)
The curious case of Finn Balor is similar to that of Bray Wyatt. Although he is the longest reigning NXT champion in history and the first WWE Universal Champion, he is currently viewed as an afterthought and a failure on the main roster.
He proved his ability by delivering a 'match of the year' candidate with AJ Styles at TLC. Yet, he lost to a returning Kane in the coming weeks. On the other hand, the Good Brothers, Anderson, and Gallows debuted as a force but are now relegated to festive-themed comedy matches.
All the three men were riding the wave of momentum as Bullet Club in Japan. There were rumors of some sort of reunion when WWE trademarked the Balor Club. However, this did not happen and WWE has clearly wasted a great opportunity. All three men are talented and unless they form The Club again, a career surge seems unlikely. Their prior experience and the huge fanbase is sure to make them reclaim their cult status Japan if they were to quit WWE.