Sometimes me and my friend would let our ponies walk around the barn (just two at a time lol) and we would watch what they would do.
My pony would always head straight for the freezer (where we keep our grain), and he'd open it! It was so bad, since he's also a very good escape artisit, I've had to put a lock on the bottom of his door so he can't open it lol.
My friends x-racer would shake his head up and down all the time, he would grind his teeth, stick his tounge out sometimes while shaking his his head lol. He was a funny boy, he also drank out of a tim horton's coffee cup lol.
While he was at a diffrent barn, he was in for 23 hours of the day so he would stand with his head in a corner, and then he'd lift one back leg up, and proceed to bob his head lol.
He stretched alot too when she'd go to bridle him