Are we just talking actual conversational use, here, or does online-only dialog count to? If so, I say:
Yarck, which is an expression of surprise and disdain over something bad that’s happened. As in “New Jersey got stolen last weekend.” “Yarck.”
nodnod Which, naturally, is like nodding, only more emphatic.
I’ve also got an innumerable variety of social actions that I picked up from AVATAR, a MUD I used to play, and that by extension absolutely nobody who hasn’t played Av understands, including (but not limited to):
comf To offer comfort.
inno To feign innocence.
toe To sheepishly rub one’s toe in the dirt.
muha To laugh manically.
blink, which is rather straightforward in terms of physical action, but can be used to express confusion or disdain. Also can be used as a question. As in: “If it wasn’t for my horse, I would never have spent that year in college.” “Blink?”
I have also perfected the use–and I wouldn’t mention this, except a number of people have commented on it as being unique; I just see it as being true to my dialect–of the double contraction. As in: "If it wasn’t for my horse, I wouldn’t’ve spent that year in college.
Outside the internet, I’ve got a few doozies I use, the most notable of which is “Hoo, dilly.” Used as an expression of surprise, to show that I’m impressed, or at the end of a really good laugh.
I’ve also taken to saying “Yeah” randomly, without antecedent, in conversation. This is most interesting when you put me with a buddy of mine, who has taken to responding every time I do so with “Word.”
As an expression of frustration or anger, I’ve always been partial to “Holy hollering hell” or “Oh, for the love of crap.” I’ve also been known to say “What in the name of galloping goatherds?”
In the tradition of AntaresJB, I’m wont to say of something horrible that it sucks “honking donkey dong.”
Not a particularly big vocabulary, I’ll admit, but a unique one.