I have a few.
One is, "O-oh!" when people say things that 'shock' me. Another is, "What's that now?" when people tell me something that frankly I don't need to hear (usually over shares about boyfriends). I suppose another similar phrase is "I beg your PARDON?"
Sometimes I refer to myself by my last name, as in, "Drapper does NOT approve!"
Another linguistic stylistic flair that I use is always Full-Naming people. Ben is "Benjamin", Matt is "Matthew!" and if I know their middle/last names, I often get those involved as well.