I've just had an epiphany
Diplomacy, but with Equine units.

Right now, Diplomacy even with fantasy maps or the like, have only army units or ships. But with unicorns and pegasi, the rules would have to be expanded.

So, having never played but the rules seem straight-forward enough, I think it would have to be like this:
Earth ponies (or Zebra) -- standard army. One unit per zone ("country" in traditional Diplomacy), one new unit created in the Spring turn if that's possible, can only move one country per turn (with an exception I have in mind)
Pegasi armies -- can travel two zones per turn, and can fly over unicorn or earth armies without interference, but will be blockaded by an intervening air army.
Armadas -- Also produced once in the Spring, but are limited to water zones. This is the exception I had in mind. I'm picturing a river splitting the map in half. Each section of the river is the same length as surrounding land zones. Armadas can attack or support an attack from their beaches but cannot occupy them. The river could be forded by land armies; essentially they just ignore it. But an opposing armada could blockade travel.
Unicorns -- A college geared toward war-training unicorn ponies would produce one army every spring. But they could not invade, only support or blockade. They also could only move one zone per turn, with the exception of that river crossing.
Batponies -- The mountains of the north, I guess, would produce one unit of batponies every spring. By default at creation they would act like pegasi BUT could spend a turn reconfiguring their make-up, and at the end of that turn would be as declared: either a water-based armada (I'm picturing cajun swamp barges, but instead of a fan, there's a bat at the back flapping his/her wings like Scootaloo does for her scooter, with either a unicorn or spear-toting batpony at the front of each barge) or to become a land unit.
The advantage of becoming a land unit is, I was thinking of allowing zones to permit multiple armies so long as they were in a different "place"; pegasi sleeping in the clouds, Earth armies on the ground, and if there's a beach, water units stay in the nearby river.

Next up I was considering including two methods of granting longer travel. One would be Appleloosa's food convoy. Once in the Fall turn that zone would create for the current owner, an "army" of food. It would be ground-bound but could occupy the same zone as an actual army.
If the owners of the food-army and battle-army are different, the owner of the food would have to declare an order to gift the food to the battle army.
Once eaten, the food-army would be "disbanded" and the next turn that army could travel two zones.
The second way, would be that owners of flight-producers could, in the Winter turn, declare an order to produce a convoy. So instead of batponies or pegasi, that zone would create one non-combatant (non occuying / non-blockading) flier. This army could merge with a ground army. If the owner of the ground army is different, both would have to declare their order to merge or the order would fail. Once merged, they would be like flying unicorns. Not able to attack, but could support an invasion, or just blockade against travel. But they could also move two zones, including bypassing hostile ground or water armies. If either owner, if they're different, orders a de-combining, the ground army will be dumped where the flight convoy was at that time.