Sofa King Killer is a sludge and doom metal band from Akron, Ohio, formed in 2000, blending Southern rock grooves with the suffocating heaviness of the Midwest sludge tradition across more than two decades of activity.

Soilent Green is a New Orleans-based sludge, death metal, and grindcore band with roots going back to the early 1990s, widely regarded as one of the most distinctive acts to emerge from the Crescent City's extreme music underground, fusing the region's murky sludge aesthetic with grindcore brutality and experimental dissonance.

Sola Angor is a sludge and doom metal band from Minneapolis, Minnesota, formed in 2022, crafting slow, heavy compositions steeped in misery and weight within a Twin Cities scene known for its commitment to underground extremity.

Sollubi is a sludge/doom metal band from Jim Thorpe, Pennsylvania, formed in 2008, crafting crushingly heavy music from the rural reaches of the Keystone State, blending the tar-thick riffs of sludge with doom's meditative weight.

Somnuri are a Brooklyn, New York sludge metal trio formed in 2017, channeling the heavy, abrasive energy of sludge metal through a dense and riff-forward approach that has earned them recognition in New York's heavy underground.

Sonic Brew is a sludge/stoner metal band from Hyrum, Utah, formed in 2017, cooking up down-tuned, fuzz-drenched riffs from an unlikely corner of the Intermountain West underground.

Sonic Command is a doom/sludge metal band from Delaware, formed in 2025, bringing the dense, slow-moving weight of sludge and doom to the nascent heavy underground of their state.

Sons of God is a southern/sludge metal band from Douglasville, Georgia, formed in 2015, merging the gritty heaviness of sludge with the swaggering groove sensibility of Southern metal.

Sons of Mourning is a sludge/stoner/doom metal band from Kansas City, Missouri, formed in 2017, conjuring heavy, grief-laden atmospheres through the slow convergence of all three of metal's most weight-bearing styles.

Sons of Tonatiuh are an Atlanta, Georgia sludge/doom metal band formed in 2010, known for punishing low-tempo riffs and feedback-drenched heaviness that draws on Southern metal traditions while incorporating the slow grind of doom.

Soothsayer are a thrash metal band from Phoenix, Arizona, formed in 2021, playing aggressive, riff-driven metal in the classic tradition of the genre within the Southwest's active thrash underground.

Sorm are a Seattle, Washington band formed in 2018 that fuses black metal's cold ferocity with the slow, punishing weight of sludge and doom metal, reflecting the Pacific Northwest's fertile ground for dark, heavy hybrid sounds.

Dallas blackened doom/sludge. Crushing, atmospheric heaviness.

Sorus is a progressive sludge metal band from Fort Lauderdale, Florida, formed in 2016, combining the slow, crushing weight of sludge with the dynamic song structures and technical ambition of progressive metal.

Sorxe is a Phoenix, Arizona post-metal and sludge metal band formed in 2013, crafting heavy, slow-burning compositions that balance visceral heaviness with atmospheric, expansive passages.