I was curious and looked it up. Corbin is tied for third most. Two matches (Joe vs Mysterio and Cesaro vs Ricochet) didn't technically "main event" but they were the last match. This doesn't include the Battle Royal tonight.
6 - Rollins
4 - Styles
3 - Corbin, Kofi, Ricochet
2 - Bryan, Cesaro, Lashley, McIntyre, Reigns, Zayn
1 - Cedric, Joe, Mysterio, Owens, Shane, Sheamus, Strowman