Changelings (d&d style), Doppelgangers, Werewolves, really any kind of shapeshifter, the more shapes/types they can take on the better.

yep, I have the same issue when congested.

I can voluntarily open my eustachian tubes and hold them open, without needing to yawn or swallow. Makes it much easier to clear the pressure in my ears when changing elevation (like when flying in a plane).