#2 Seth Rollins vs. Cesaro at WrestleMania 37
With this story already underway, WWE could extend it until WrestleMania. Seth Rollins attacked Cesaro on the former's first appearance on the blue brand in three months.
The Swiss Superman had an incredible showing in the SmackDown Elimination Chamber Match following that, and a program with a dastardly heel like Rollins will keep him in the upper echelons of SmackDown. The two of them could face each other at Fastlane with a WrestleMania blowoff sounding like a great idea.
Rollins could cheat to win their first match before Cesaro picks up a huge victory at the Show of Shows, or WWE might opt to tell a longer-form story between the two in-ring experts. A 'Mania match between them would be phenomenal, especially in their current roles. Rollins can do a lot of good for Cesaro and his upward trajectory in WWE.
WrestleMania features everything - Superstar power, grand entrances, major surprises, celebrity involvement, and great in-ring action. Seth Rollins and Cesaro would fulfill the role of being the technical masterpiece in it.