Thrash/sludge metal band from Toulouse in southwestern France, active since 2015. Their sound merges thrash velocity with sludge weight from the Occitan capital.

Insidious Process is a black/sludge metal/crust punk act from Gothenburg, Sweden, active since 2009 and fusing black metal aggression with punk-influenced rawness and energy. The project bridges extreme metal and underground punk traditions.

Insuiciety is a sludge metal band from Berlin, Germany, active since 1993, making them one of the city's longest-running heavy acts with over three decades of oppressive, slow-grinding sludge. The band channels Berlin's gritty energy into tar-thick compositions of crushing heaviness.

Inverted Mind is a sludge/stoner metal band from Kraków, Poland, active since 2012 and delivering fuzz-laden, groove-heavy riffs through a haze of overdriven amplification. The project channels the riff-worshipping spirit of the genre.

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.