RockLobster
King in the North
Do you ever listen to Steven Wright? You'd love him, just as good one liners as Mitch.
Steven Wright is another good one, yes.
You'd mentioned John Mulaney before, and he's absolutely hilarious (shame that the concept of his sitcom was lost on the wide-audience). You also mentioned Gaffigan, he's good for some laughs as well.
Dimitri Martin is one of my favorites right now, he's pretty good. And honestly, I know some people didn't like (or understand) his show, but Jerry Seinfeld's stand-up is definitely among the top. He just gets it.
Martin told a good Wright story on The Nerdist Podcast a while back...I'd try to re-tell it right now, but I feel like I would mess it up, but just go look it up and I think you'll have a chuckle.