Well, this may get locaked, just because it's been done a couple times, but I'll bite.

Heavy Metal:
King Diamond/Mercyful Fate
Motorhead
Iron Maiden
Judas Priest

Power/Speed:
Blind Guardian
Demons and Wizards
Gamma Ray
Iced Earth (I know it's debateable, but for the sake of convieniance)

Thrash:
Overkill
Exodus
Megadeth
Kreator
(There are many others, but I'm trying to limit to four per genre)

Doom/Stoner/Sludge:
High on Fire
Sleep
Cathedral
Corrosion of Conformity

Death/Grind:
Entombed
Napalm Death
Death
Bolt Thrower

Black:
Immortal
Emperor
Usurper
Celtic Frost

Other:
Voivod
Therion
Type O Negative
Vintersorg

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