#4 Shane McMahon
Shane McMahon and Roman Reigns have been at odds ever since the latter delivered a Superman Punch to his beloved father, Vince McMahon. If you notice the segment where Rowan was unmasked as the man behind the attacks, when Daniel Bryan confronted him, it seemed like Rowan said that someone made him do it. Now, who could have that kind of sway over a man like Rowan, is something everyone's been wondering.
The clear answer and the simple answer is Shane McMahon and I can imagine him taking on Roman Reigns down the line in what could potentially be a big match. Bryan and Rowan could certainly enter the fray later, but for now, I can absolutely imagine Shane McMahon and Reigns taking each other on at Clash of Champions. In fact, let me build an interesting scenario for you which could essentially lead to the next chapter.
Roman Reigns is able to take Shane McMahon out and stands tall after the match is over, celebrating his big win, and it is then that yet another attack is made on his life, leading to an eventual program with someone like Daniel Bryan presumably at Survivor Series 2019.