There have been other sub categories of doom metal. Some have a small twist from the original and some are mixed with other metal genres. This list is the most popular sub genres of doom metal.

Doom Metal Traditional

The beginning of doom metal. With doom metal starting in the 90's most bands today still fall into this sub category. Including a a slower tempo with heavy distortion sound. You will find plenty of clean vocals, with some high pitched screaming.Reverend Bizarre, Witchcraft and Ogre are a handful of the bands that are in Traditional Doom Metal.

Epic

This sub genre is much like Traditional metal. With the music being comparable the style of vocals is what sets it apart. There is cleaner singing in Epic metal.Included bands in this category are Solstice, Solitude Aeturnus, Candlemass and Doomsword.

Stoner Metal

This is called Psychedelic Metal. Why you might ask, because it has psychedelic styles to the music. Watch for lots of effects with synthesizers and guitar pedals when listening to this style of music. Usual guitar effects are going to be flanger, phaser and fuzz. Stoner bands were the initial artists to make use of effects and guitar pedals. Pay attention to Electric Wizard, Sleep, Sons of Otis, Kyuss and Acid King for some stoner metal music.

Sludge Doom Metal

If you put southern rock, metal and hardcore punk all in one you get sludge metal. A fast tempo is very common in this style of music. Sludge metal has more double bass drum beats and more of a raw distortion sound guitar. Everyone sings about something different but a common topic is drugs, politics and society.Eyehategod, Grief, Crowbar and Acid Bath are a handful of examples of Sludge metal bands.

Death

Putting together slow tempos plus some really heavy distortion provides you with more of a death metal feel. The vocal style is the biggest change in this sub genre. Snarls and growling are the most typical ones. With more double bass drumming than typical doom metal. There has been many ties with bands like Hellhammer and Celtic Frost.For more info tune in to Autopsy, Winter, My Dying Bride, Paradise Lost and Asphyx.

Black Doom Metal

Black Doom metal is typical Doom metal with the elements and features of Black metal. There will be lots of high pitched scream with a huge amount of raw distortion. They also play with a slower tempo or rate to their music.For a few bands in Black Doom metal tune in to Nortt, Dolorian, Gallhammer and Ajattara.

Where is Doom Metal Headed?

The above mentioned of a few of the other sub categories of doom metal. You can even find more than these. It started in 1990's and is growing today. There isn't a ton of new bands that belong to this genre, but it does keep growing.