Haven't been riding for that long but:

Eagles (very common here, they will sit on posts as you ride right underneath them)
Heron
Turtles
Coyote
Rabbits

The rabbits must be the dumbest animals, I can see them from 100 hundred yards away and they don't move until you are 4 feet from them. But they don't jump into the bush, they go across the trail right in front of you and then sometimes change their mind and come right back across. I'm on to their foolishness now but they were stressing me out for a while doing that!