When it comes to creatures in fantasy, authors can be really imaginative. There are the ‘classical’ creatures like werewolves, vampires, dragons and many others and authors (including those of computer games) seems to be able to create several more with different place on the scale between any large beast and human. Or just really scary beasts with some slight sentience.
The fact that I started reading a bit more seriously only two years ago might be a factor, but so far I have yet to encounter a book that would use elementals, let alone in such scale as they are used in World of Warcraft. That is despite the fact that creatures related to the four elements appeared in old myths (ancient China, Greece) and some others are most likely inspired by them (Russian Ded Moroz – (Great)father Frost or other examples from Slavic myths).