Vulgars.

The same as Imps only faster and they do a lot more crawling too.

Bruiser.

Half mecahnical monsters with computer monitors for there mouth, they have a tendency to hide as wall monitors and then bust through the walls after you.

The Forgotten.

Identical to the lost souls from DOOM and DOOM II.

Hell Hunters.

Floating, legless hellknights that seem half mechanical now, like the pinky demon. These monsters have the ability to warp time.