InVitro is a sludge metal/metalcore band from Florence, Italy, active since 2016 and delivering crushing, suffocating heaviness from the low end. The project channels the abrasive, punishing weight of sludge metal.

Invouta is a sludge/doom metal band from Fribourg, Switzerland, formed in 2018, crafting heavy, slow-motion compositions in French. With releases including Ainsi-soit-il, L'appel de la corde, and Face à face, the band has been making metal for years and solidified their current formation in 2022.

Iona Death Cult is a progressive sludge metal band from Bray, Ireland, active since 2017 and delivering crushing, suffocating heaviness from the low end. The project channels the abrasive, punishing weight of sludge metal.

Irden is a black/sludge/post-metal band from Osnabruck, Germany, formed in 2020, combining the atmospheric hostility of black metal with the tar-thick heaviness of sludge and post-metal's expansive dynamics. The band creates a dense, multi-layered sonic experience from Lower Saxony.

Iron God is a sludge metal band from Stockholm, Sweden, active since 2018 and delivering crushing, suffocating heaviness from the low end. The project channels the abrasive, punishing weight of sludge metal.

Iron Monkey are a legendary sludge/doom metal band from Nottingham, formed in 1994 and signed to Relapse Records. Their crushing sound of fuzzed-out guitars and misanthropic snarls has made them vanguards of the sludge doom genre across releases like 2024's Spleen & Goad.

Iron Pike is a sludge/doom metal act from Malmö, Sweden, active since 2015 and channeling monolithic heaviness through its doom metal framework. The project delivers oppressive, glacially paced compositions.

Iron Sect is a sludge/stoner/doom metal band from Saint Petersburg, Russia, active since 2024 and delivering crushing, fuzz-laden heaviness where doom's oppressive weight meets stoner metal's hazy grooves. The project channels low-end power and psychedelic atmosphere.

Iron Slug is a German sludge metal band formed in 2024, dealing in the thick, tar-heavy riffs and crushing slowness that define the genre. The band delivers oppressive sonic weight with a deliberate, steamrolling approach.