Oldschool/Heavy metal: does Iron maiden fit here?
Thrash Metal: Testament, shit, if that fits...
Death Metal: Cryptopsy or Nile
Black Metal: Hecate enthroned or Lord Belial
Symphonic black metal: Nazgul(ITALY!!!) or Dimmu Borgir
Melodic black metal: Mourn in silence
Melodic Death Metal: tough... Kalmah or Skyfire
Power Metal: falconer, CoB if valid
Prog Metal: ?
Doom Metal: fuck it, i really feel like Insomnium is doomish, lyrics and pace...
Tech Metal:?
Grindcore:
Viking/folk: Mithotyn, Ensiferum ...any band in this/these genres really

That was too hard. I find it difficult to choose a band over another in many cases, as you can see