#2 Surprise challenger for the US title

Luke Harper is one of the most underrated WWE Superstars out there. Even at 40 years old, he is in very good condition and can have good matches with anyone on the roster.
The former Intercontinental Champion in his own right has enough charisma for a solo run in the company.
There have been rumors that Samoa Joe is going to face John Cena for the US Championship at WrestleMania 35. While that match is definitely a top draw, nothing has been confirmed yet.
WWE can bring back Luke Harper to face Samoa Joe for the US title. For a start, Harper is a WWE regular and it is time regulars are given more preference than part-timers.
Having already won the Intercontinental Championship and tag-team titles, it would make a lot of sense for Harper to go after the US title.
The hard-hitting matches between Samoa Joe and Harper could be a sight to behold for the fans if WWE does book them in a feud.