In addition to doing funny original characters, like Garth and the Church Lady, Dana Carvey was a master imitator of SO many people, including George H.W. Bush & Johnny Carson. What's rather cool about Carvey is that he ended up withdrawing from the limelight because he didn't want his kids to grow up with a dad who was gone all the time.
Ah, Mike Myers. He's just so lovably goofy as SNL characters like Simon ("Don't look at my bum"), Linda Richman (based on his mother-in-law) and Dieter from Sprockets. He played two roles in 1993 movie So I Married an Ax Murderer. He was both the male lead and the male lead's severely-Scottish father. And of course it was his character Austen Powers that put him into the major big time.