Fearadox is a technical sludge metal band from Malmo, Sweden, formed in 2025. They bring technical precision to sludge metal's heaviness from Sweden's third-largest city at the southern tip of the country.

Fehler is a sludge/doom metal and hardcore band from 's-Hertogenbosch in the Netherlands, formed in 2019. Their German-derived name — meaning 'error' or 'flaw' — matches the abrasive, confrontational character of their sludge-soaked hardcore from the North Brabant capital.

Feral Thrust is a sludge metal and crust band from Milan, Italy, formed in 2010 alongside the Limbs Disarm DIY collective. Their 2018 release Il Grembo della Rovina explores humanity's destructive relationship with nature through two extended tracks of blackened crust and stenchcore, recorded at the Kalashnikov collective's headquarters.

Fever Sun is a black/sludge metal project from Pordenone, Italy, self-described as a 'local discomfort unit.' Their 2025 debut Index spans four tracks across thirty-two minutes of atmosphere-heavy black metal fused with sludge and doom, praised for its balance of crushing weight and compositional nuance.

Fiasko is a post-metal band from Warsaw that has evolved toward sludge/black metal since their 2017 formation. Their stylistic journey from atmospheric post-metal to more aggressive sludge and black metal territory mirrors the restless creative energy of the Polish capital's underground scene.

Fields of Locust is a doom/sludge metal band from Patras, Greece, active since 2011 with releases including Nowhere Left Now To Call Home and Ripples In Stagnation. The band delivers introspective, socially conscious doom and sludge from the Peloponnese.

FiftyxBrick is a sludge metal band from Liverpool, England, formed in 2020. The band delivers thick, abrasive sludge metal from the Merseyside city.

Fire Walk with Me is a sludge/doom metal and drone band from Písek, Czech Republic, formed in 2015. Their 2015 album "...neither the fires of hell will guide us home" spans six tracks over 60 minutes, blending post-metal, psychedelic, and sludge elements with contributions from guitarist Max Abt on synthesizer and piano alongside a four-piece lineup.

Fire Walk with Us is an atmospheric sludge and post-metal/post-rock band from Amsterdam, active since 2008. Their Twin Peaks-referencing name hints at their taste for the uncanny and atmospheric, weaving dense sludge textures into sprawling post-metal compositions.