#1 Adam Cole

Adam Cole is undefeated in singles competition. That is a fact. He's only competed in one single's match against Eric Young, which he won but it still counts. He's never been beaten in singles competition in the WWE.
Which is more than can be said for Kyle O'Reilly and Bobby Fish, his The Undisputed ERA compatriots who both debuted in losing efforts against Aleister Black. This makes Cole the most successful member of his stable in singles competition.
Cole is being built up as the one to take the belt off of Drew McIntyre and is due to face the NXT Champion in a title match the night before NXT TakeOver: WarGames where Cole and his faction are set to do battle in a historic WarGames match. But for now, from his one singles match, he's unbeaten.
Becky Lynch has been challenged HERE.