i imagine spiral dragons to have various asian accents.
and guardians maybe slightly Jamaican sounding? but since they wander it depends.
Ridgeback: thick German accents [“MEIN. MEIN, MEIN, MEIN. NEIN, ZAT IZ MEIN.”]
Wildclaws: Maybe African?
Tundra: Definitely Russian 
Skydancers: FRENCH, AHAH
Fae: Australian?