Dragons......
Put dragons into your RPG, thing about J.R.T, he never put enough dragons into his storys, sure there was the Hobbit, but that was about it (Balrog doesn't count, that was a demon from the old world).....>.>
Hum, what else, perhaps Ogres, which are different from Trolls or Orc's or goblin men, then there's the Simarillion (SP? I know I spelled it wrong, someone help me out here) which was a collaberation of writings that Tolkein did on the World of LOTR which featured many other critters and such, most of them escape me at the moment, but there where a few.
Along with this though you could take other animals from mythology, the cockatrice, basilisk, things like this. Also, try to use sub-refference from the movies and such, Example....Gorn was a big catapult in the shape of a wolf that was partially set on fire to raid Gondor, but what if Gorn was based off a real critter in the Lord Of The Ring world, why not make yourself a giant fire breathing wolf? Then there's the Ents, they where beings whom sheppered the trees, why not have beings made of ice and such? Stuff like this will make making foes and such easier.
Hope this helps some,
God bless,
Archan