Demut
Veritas vos liberabit
So far we have seen two: The regular, fire-breathing kind on the one hand and some sort of frost dragon that can slow you down on the other hand. Todd Howard said that there will be more kinds than that (although not many more). What other ones could there be? I can’t really think of more than that. A water dragon seems unlikely. An earth or stone dragon would also be weird. So what sorts could be left if not the other elements?