R. Josef is a solo atmospheric sludge and post-black metal project from Leipzig, Germany, formed in 2019, with all music written and performed by a single musician. Their 2019 Panoptic EP was released on cassette via Bharal Tapes in a limited run of 66 handmade silkscreened copies, delivering four tracks of dense sludgy post-metal.

R.O.L.F. is a doom/sludge metal and death 'n' roll band from Algeciras in southern Spain, active since 2009. The band channels heavy, low-end-driven doom and sludge with rock 'n' roll swagger from the Strait of Gibraltar.

Abruzzo act from Atessa that evolved from grind 'n' roll origins into a death 'n' roll, sludge, and stoner metal hybrid since 2011. Their stylistic evolution reflects a band constantly discovering new ways to channel aggression through groove-laden heaviness.

Radien is a sludge metal band from Helsinki, Finland, formed in 2016. Named after the supreme deity in Sami mythology, the band delivers heavy sludge from the Finnish capital.

Rage of Samedi is a doom/sludge metal band from Zweibrücken in the Rhineland-Palatinate region of Germany, formed in 2014. Their releases including Blood Ritual and Children of the Black Sun channel dark, ritualistic themes through heavy, low-end-driven doom and sludge.

Raging Sloth is a sludge and doom metal trio from Munich, Germany, formed in 2018 and featuring Max on bass and vocals, Mischa on guitar, and Jonas on drums. Self-describing their sound as 'heavy dystopian sounds in the realm of sludge and doom metal,' their releases include The Descent EP and the track Event Horizon.

Raging Speedhorn is a hardcore/sludge metal band from Corby in Northamptonshire, England, with renewed activity from 2019. The band delivers punishing sludge-hardcore from the East Midlands steel town.

Raglefant is a sludge/doom/stoner metal band from Zarautz on the Basque coast of Spain, formed in 2018. The band delivers heavy, fuzz-laden doom and sludge from the Cantabrian surf town in the Basque Country.

Milan sludge and stoner metal act formed in 2018, delivering crushing heaviness and fuzz-drenched riffs from Italy's economic capital. Their downtempo approach channels the oppressive weight central to the sludge tradition.