i don't really like all the lame modern genre stratification, but just to make this more interesting i'll use RYM's sub-genres plus maybe a few of my own. definitely straining to fit certain albums in when they fit better elsewhere, don't @ me.
alternative metal: katatonia - tonight’s decision
nu metal: system of a down - toxicity
industrial metal: rammstein - mutter
avant-garde metal: ved buens ende - written in waters
(traditional) black metal: mayhem - de mysteriis dom sathanas
atmospheric black metal: burzum - hvis lyset tar oss
melodic black metal: sacramentum - far away from the sun
pagan black metal: graveland - thousand swords
symphonic black metal: summoning - dol guldur
war metal: axis of advance - strike
raw black metal: wolfnacht - heidentum
folk metal: nokturnal mortum - voice of steel
orthodox black metal: deathspell omega - si monvmentvm reqviris circvmspice
death metal: the chasm - deathcult for eternity: the triumph
brutal death metal: suffocation - effigy of the forgotten
melodic death metal: at the gates - with fear i kiss the burning darkness
technical death metal: atrocity - longing for death
death doom metal: fleshcrawl - descend into the absurd
deathgrind: kataklysm - sorcery
goregrind: carcass - symphonies of sickness
grindcore: terrorizer - world downfall (actually more deathgrind than the above but w/e it has grindcore primary on RYM)
doom metal: warning - watching from a distance
traditional doom metal: saint vitus - s/t
epic doom metal: candlemass - epicus doomicus metallicus
funeral doom metal: skepticism - stormcrowfleet
sludge metal: harvey milk - a small turn of human kindness
gothic metal: my dying bride - the angel and the dark river
heavy metal: cirith ungol - king of the dead
NWOBHM: satan - court in the act
power metal: dark moor - the hall of the olden dreams
USPM: jag panzer - ample destruction
prog power metal: fates warning - the spectre within
prog metal: adramelch - irae melanox
speed metal: helstar - nosferatu
thrash metal: slayer - hell awaits
technical thrash metal: voivod - killing technology
crossover thrash: carnivore - s/t
BONUS: EPs/demos
heavy metal: sortilege - s/t
prog/power metal: kingsbane - demo 1991
death metal: catacomb - in the maze of kadath
black metal: sodom - in the sign of evil
melodic black metal: trails of anguish - relentless abhorrence of misery's grievance
melodic death metal: cromlech - and darkness fell
thrash metal: destruction - sentence of death