All mountains on Titan are named for fictional peaks in Tolkien’s books. In addition to Mount Doom, there is Mount Erebor, the Lonely Mountain, where Bilbo and company travel to fight the dragon Smaug in The Hobbit and also the Misty Mountains which house the Dwarven city of Khazad-dum and the mines of Moria, where the dwarves dug too deep, unleashing the Balrog that kills Gandalf (well, almost killed him).
The plains of Titan are named from planets in Frank Herbert’s Dune series such as Arrakis Planitia, named for the planet where Paul Atreides becomes Muad’Dib and learns to ride the mighty sandworms. The Chusuk plain and Sikun labyrinth are also named for planets in the Dune series.
There are many other features in the Solar system that do not follow the habitual mithology nomenclature. You can see the current list of categories in the IAU's web site.
Note. As many of you will know, the post title is the Khuzdul battle cry of the Dwarves and its translation is Axes of the Dwarves! The Dwarves are upon you!