Neurosis, Eyehategod, Iron Monkey, Melvins, The Abominable Iron Sloth, Made Out of Babies, Latitudes, Grief
Though I prefer when sludge is watered down with post-metal, to be honest. I.e., Rosetta, Cult of Luna, Giant Squid, A Storm of Light, Year of No LIght. Neurosis has a strong post-metal feeling to their music as well.