#3 AJ Styles

AJ Styles started off 2018 as WWE Champion. He successfully defended the WWE Championship against Kevin Owens & Sami Zayn (in a handicap match) at Royal Rumble and against Kevin Owens, Sami Zayn, Baron Corbin, Dolph Ziggler, & John Cena at Fastlane.
The Phenomenal One head into WrestleMania strong and defeated Shinsuke Nakamura in a dream match for the WWE Championship at WrestleMania 34 and feuded with Shinsuke Nakamura until Money in the Bank. AJ Styles vs Shinsuke Nakamura at Money in the Bank was a match of the year candidate and after that, AJ Styles really started to hit the ground running. He beat Rusev in another good match at Extreme Rules and had 4 good matches with Samoa Joe afterwards.
AJ Styles eventually lost the WWE Championship to Daniel Bryan in another good match and then lost to Daniel Bryan in a rematch at TLC which was one of the best matches of the year. Since then, AJ Styles has seemingly turned heel and will likely enter the Royal Rumble.