I've eaten whale steak, puffin breast, and duck tongues (and brains). Had a gator sausage, once, too, but it had been cut with pork and, while good, I can't say that I really know what gator, alone, tastes like.
Also, when my friend's wife gave birth to their second daughter, he took the placenta home and made it into a small meatloaf. The iron flavor was super strong (like liver times ten) and I found the preparation a little off putting. If I had a chance to prepare placenta, myself, I'd either make a pate to smear on cocktail toasts or cut it into slices and sautee it along with some onions (maybe mushrooms).
Beyond that, I ALMOST ate horse, once, but it was a $30 dish and I had already stuffed myself and wasn't in a position to spend the money just for a few bites. Kind of regret it, though.