I included them all, even the ones I wouldn't consider, but I'm especially looking for the two you think are the most nightmarish ones, whether you may find them disturbing or scary, and whether hostile or not.
I also didn't include subtypes, so if you would choose the wrathrat then pick the Giant Rat, for example.
I probably got excessive with the inclusiveness, but you never know with phobias. Cotton balls or helium balloons, anyone? However, I did exclude the arguably cutest or inoffensive ones.
EDIT:
Drat! I'm an idiot, and when I was finalizing my list I omitted the trepors. They're not your usual monsters: not at all hostile unless you threaten them, and they even shout gratuitous greetings to nobody in particular, but they have that face like the Zanties from the Outer Limits which did creep me quite a bit.
So, please let us know if you would've liked to vote for them, and consider that a bonus point!