#4 Braun Strowman
The Wyatt Family was a very interesting stable and had tonnes of potential. Every iteration of the creepy bearded swamp-dwellers could have sent Bray Wyatt over to the next level. Right in the middle of the group's run came Braun Strowman, a giant that nobody had ever seen before.
Strowman was a key member of Wyatt's cult for a year between 2015 and 2016, before being separated from his 'family' via the Draft. Since then, the two have hardly interacted. Strowman and Wyatt did have a confrontation at Survivor Series that year, with the Monster Among Men going after his former leader.
The Fiend did attack Strowman last fall, but nothing came of it. It seems like a no-brainer for both men to face each other later in the year, with a built-in story to it.
A match with The Fiend would be much better than anything Braun Strowman is doing currently as the Intercontinental Champion, while he would be another great victim for The Fiend to add to his collection.