Forced to Decay was a death metal/grindcore band from Solingen, Germany, active from 1994 until 2001. Over their nine-year run, they played more than 350 shows and released three CDs/LPs alongside several other recordings, with members going on to form The Other and Kontrolle after the band's dissolution.

Foreboder is a doom/sludge metal and hardcore band from Selby, England, formed in 2018. The band merges doom and sludge metal's crushing weight with hardcore's aggression from the North Yorkshire town.

Foreshadower is a doom/sludge/post-metal band from Copenhagen, Denmark, formed in 2019. The band layers doom metal's weight, sludge metal's grime, and post-metal's atmospheric expansion into dense compositions.

Forever Wasted is a sludge/doom metal band from Kyiv, Ukraine, active since 2011. They deliver the heavy, intoxicated weight of sludge and doom from the Ukrainian capital's diverse metal scene.

Forge of Clouds is an atmospheric sludge/post-metal band from Lubin in the Lower Silesian copper basin, active since 2011. Their evocative name captures the atmospheric, textural quality of their post-metal approach — heavy music shaped and reformed like clouds in an industrial forge.

Formalist is a sludge/drone/doom metal supergroup from Piacenza, Italy, formed in 2014 by members of Forgotten Tomb, Malasangre, and Viscera///. Their releases We Inherit a World at the Seams and No One Will Shine Anymore aim to 'open new gates to total sonic horrors,' combining the heaviest elements of their parent bands into crushing experimental doom.

Fosso della Carogna is a sludge metal band from Fermo in the Marche region of Italy, formed in 2024. Their name — Italian for 'carrion ditch' — sets the tone for their grimy, down-tuned sludge metal drawn from the Adriatic coast underground.

Frankreich is a sludge metal/noise rock band from Cherbourg, France, formed in 2017. The band — whose name is the German word for "France" — blends sludge metal with noise rock from the Cotentin Peninsula.

FreeHowling is a death/sludge metal turned deathcore/hardcore band from Hauts-de-France, formed in 2021. The band evolved from sludgy death metal origins into heavier deathcore and hardcore territory.