#2 Daniel Bryan
The feud between Daniel Bryan and The Miz started the moment Bryan debuted as a competitor on NXT with Miz as his mentor in 2010. Later on in the year, they would feud over the WWE United States Championship.
The current feud started two years ago in 2016 during Talking Smack when Bryan was the SmackDown General Manager. It was one of The Miz's best promos to date and has led to SummerSlam 2018 where Daniel Bryan and The Miz will likely have a match.
When both Bryan and Miz's careers are over, Bryan may likely move up to becoming the best rival of The Miz ever.