The first band which comes to my mind is Midnattsol:
Also check out Nemesea's first album "Mana" (if you find it anywhere), but better avoid the albums they released afterwards:
As regards folk-influenced stuff, you might like Bergtatt's first album "Røtter" or at least some songs on it, as e.g.:
Their new stuff (featuring a new vocalist) is more folk and rock and can hardly be considered metal at all, thus it's possibly too soft for your taste, but try it nevertheless: