I love Heavy Metal and I could write about it for hours, but I’ll try and provide a brief summary for the genres I like best.
DEATH METAL
Sounds Like: guttural growling vocals, alternating slow and fast tempos
Lyrics: death, dead bodies, diseases; occasionally Satanic or political
(Grindcore is basically Death Metal performed by punks, with political lyrics)
Typical Bands: Napalm Death, Carcass, Death, Morbid Angel, Autopsy
Record Labels: Earache, Peaceville, Relapse, Roadrunner
BLACK METAL
Sounds Like: guttural growling vocals, extremely fast tempos
Lyrics: Satanism, burning churches; winter; pagan Scandinavia, occasionally Nazism
Typical Bands: Darkthrone, Mayhem, Burzum, Emperor, Satanic Warmaster
Record Labels: Moonfog, Osmose, Peaceville
(Black Metal is also typified by the black and white “Kiss” style make-up that the performers wear.)
THRASH & SPEED METAL
(Purists differentiate between the two, IMO they’e close enough to group together)
Sounds Like: vocals can vary between growling and actual singing, fast tempos with lots of catchy guitar riffs and complicated guitar solos
Lyrics: rock and fantasy imagery, sometimes politics or Satantism; drugs and alcohol
Typical Bands: Metallica, Slayer, Megadeth, Anthrax, Exodus
Record Labels: Megaforce, Music for Nations, several major labels
PROGRESSIVE METAL
Sounds Like: heavy metal with jazz and progressive rock inspired tempo changes
Lyrics: fantasy; philosophy; concept albums
Typical Bands: Dream Theater, Queensryche, Cynic
Record Labels: various major labels
DOOM METAL, STONER METAL etc
Sounds Like: Black Sabbath, very slow tempos
Lyrics: drugs, magic & wizardry
Typical Bands: Sleep, Cathedral, Boris, Electric Wizard
Record Labels: Southern Lord, Rise Above
Again, IMO, the remainder of the genres you’ve listed are so similar that they can be grouped somewhere in the four wider types above.
For example, I love Grindcore, but I also realize that to any casual listener it’s going to sound exactly the same as Death Metal, so there’s not much point in sub-categorizing it.
Punk and hardcore music also suffers from the same kind of ad nauseam sub- and sub-subdividing. It can get quite inane sometimes.
After all most modern music critics don’t bother to classify Skifflepsychedelicpopfolkrock bands like the Beatles, Randbpsychedelicpopfolkrock bands like the Rolling Stones, and Neoskifflepsychedelicpopfolkrock bands like Oasis into different genres.