#4 Bobby Lashley
Now that he's moved on from his storyline with Rusev, Lana and Liv Morgan, Bobby Lashley has seemed a little directionless. He still has matches but there don't appear to be any angles at the moment for The All Mighty. Lashley is not the most charismatic of Superstars but he is still a talented and useful performer on the roster.
Want a veteran specimen for a young up-and-comer to tangle with? I give you Lashley. Do you want that physical threat to be overcome in a good angle? There's Lashley.
Since The All Mighty isn't getting into the WWE Championship picture at the moment, a great use of his talents would be to continue his work as a mid-card heel.
Monster heels like Brock Lesnar and Lashley provide an almost insurmountable physical challenge for faces to overcome. If a person like Mysterio, Carrillo, Ricochet or Aleister Black wins the US Championship this year then Lashley would be a serious threat to their title reign. And if they want to have Lana involved in some fashion, it would be great as well since she gets a lot of heat from the WWE Universe.