All elemental attunements are listed here. Even if a dragon species is listed with certain attunements does not cap the possibility of having non specified ones. Even dragons that are “ill suited” for a particular element can end up the element they are usually not capable of being.
Normal list:
Water
Fire
Earth
Electricity
Wind
Mind
Rare Attunements
Shadowbane (Vaqaxalan exclusive)
Solluminant (light)
Corewalker (Necromancy)
Icebane (rare sub element of water)
Ivyseeker (rare sub element of earth, attunements to plants)