Oh, for Pete's sake!
Oh, for pity's sake.
Oh, for cryin' out loud.
Jesus, Mary, and Joseph!
What on God's green earth is (this, that, going on)
Lord love a duck!
God BLESS this (thing, object)
I know there's religious overtones there, but that's all I can think of at the moment. I cuss. A lot. So I don't have a bunch of non-swears in my repertoire.