Morning Death is a atmospheric sludge/progressive metal band from Rome, Italy, formed in 2022. They craft intricate progressive compositions with technical ambition.

Morpholith is a stoner, sludge, and doom metal band from Reykjavík, Iceland, formed in 2018. They channel crushing heaviness from the volcanic island.

Mortier is a doom and sludge metal band from Lille, France, formed in 2020. Their French name meaning "mortar" captures the crushing, grinding weight of their doom-sludge.

A stoner-sludge quartet from Ghent, Belgium, describing their music as a tunnel-vision trance built on doomed riffs and relentless rhythm, with acknowledged debts to Kyuss, Sleep, Electric Wizard, and Eyehategod. Their debut album 'Diptera' arrived in February 2023 on eight tracks of psychedelic heaviness, and a second album is forthcoming on Pesticide Records.

Moss is a sludge, drone, and doom metal act from Southampton, delivering some of the slowest, heaviest, and most punishing music to emerge from the UK underground since 2005. Their glacial tempos and overwhelming volume have made them a reference point for extreme doom.

A doom and sludge metal act from Scotland, Moth Corpse emerged in 2024 with a sound built on crushing, down-tuned riffs and agonized vocals. The band channels the grey, oppressive atmosphere of the Scottish landscape into suffocating heaviness.

A atmospheric sludge metal act from the northern Portuguese coastal city of Viana do Castelo, Mother Abyss has been crafting heavy, oceanic compositions since 2020. The band channels the Atlantic coastline's power into crushing, immersive sludge.

Mother Knife is a blackened sludge metal band from Manchester, England, formed in 2025. They fuse blackened fury with crushing sludge metal.

Mother Susurrus is a psychedelic sludge and post-metal band from Tampere, Finland, formed in 2010. They fuse psychedelic textures with crushing sludge and post-metal's atmospheric expansiveness.