Oof good question! These aren't in order, just the top 5 I can think of:
Oneyplays
Neocranium
MarioInATopHat
Vinny from Vinesauce
VideoGameDunkey
(I also want to mention these YouTubers: JFJ, SnapCube, Noodle, Max0r, Wrath Club, 2ndJerma, SuperMega, Nothin but Lag, General Sam, Childish, uricksaladbar, Mikeburnfire and his best bud Zach Hazard, and Crowbcat.)