The Graug (Shadow of Mordor)
First mentioned by Elfgore
The last mount on the list is a reluctant mount at best. Shadow of Mordor's Graug is an amphibious creature that resembles a giant troll. The huge beast has massive claws and teeth, and they can be hard to take down due to their natural armor. That said, if you can sneak up on the Graug and slice its ankles, then fire an Elf-shot into its head, you can dominate the beast and use it as a mount. Since that means you get to rampage around and smash your enemies with a giant monster, you're going to want to do that.