I've been wandering the PTR a bit, and while I don't know if there are others around, there is at least one new beast out there in the 'old world' that is a completely new mob (with an old skin)
Plainsland Cheetah: using the
These fellows 'mark' the areas the cheetah cub spawns, and they themselves are tameable.
More beasts, though not tameables: apparently almost all of the 'big critters', such as cows, deer, and rams, are now beasts instead of 'critters'. No doubt this is to help keep the tameable versions a little more obvious, but I could be wrong.