Backbone is a progressive death metal band from Resistencia, Chaco, Argentina, emerging from the ashes of previous local projects including Melisma and Alhazred. Their debut EP "R'lyeh"—titled after the sunken city of H.P. Lovecraft's mythology—drew notice for combining death metal brutality with groove and progressive elements unusual for the region's underground scene.

Backstroke is a thrash metal band from Brasília, Brazil, formed in 2019. Operating out of the capital's underground scene, the band channels straightforward, aggressive thrash in the Bay Area and Brazilian tradition. They remain active as an independent act in the Brasília metal community.

Bacteremia is a Brutal Death Metal band from Medellín, Colombia, formed in 2006 and signed to Permeated Records. They released their debut full-length "Cerebral Wrong Settings" in 2013, followed by "Furiously Reduced" in 2017, a nine-track album exploring themes of mankind, death, and pathology.

Bacteria is a heavy/thrash metal band from San José, Entre Ríos, Argentina, active since 1999. The band appeared on the 2009 compilation "2dos. Puro Metal" released by Kodigo Rojo Records out of Concordia, Entre Ríos, one of the few regional metal labels documenting the underground scene in that province.

Bad Resilience is a grindcore and noisecore project from São Paulo, Brazil, founded in mid-2024 by musician Rodrigo Chenta. The project fuses diminutive riffs with raw blast-beat grind, drawing lyrical themes from Christian theology — including kenosis, ordinances, and martyrdom — with lyrics in both English and Spanish. Their debut album Mutilated Head (2024) arrived alongside the single Stoning, establishing a deliberately brutal and theologically charged identity.

Bad Salad is a progressive metal band from Brasília, Brazil, formed in 2007 by brothers Thiago Campos (guitar) and Felipe Campos (bass) alongside drummer Caco Gonçalves. Their debut album Uncivilized (2012) earned international critical acclaim for its complex songwriting and songs regularly exceeding ten minutes, drawing comparisons to Dream Theater and Opeth; the follow-up EP Puzzled appeared in 2013. The band was handpicked by Mike Portnoy to perform on the Progressive Nation at Sea cruise in 2014, one of the few Brazilian acts to achieve that distinction.

Bad Taste is a death/thrash metal band from Porto Alegre, Rio Grande do Sul, Brazil, formed in 2017. They operate out of the South Brazilian underground, a region with a strong tradition of extreme metal, playing aggressive thrash rooted in the death metal aesthetic. The band remains active as an independent act.

Badhead is a thrash/crossover hardcore band from Brasília, Brazil, formed in 2015. Blending the pit-ready aggression of hardcore punk with the riff-driven attack of thrash metal, they contribute to the capital's vibrant underground crossover scene. The band remains active as an independent act.

Badtrip Surfdeath is an instrumental power trio from São Paulo, Brazil, active since 2008 and coined the term 'surfdeath' to describe their collision of hardcore, grind blasts, black metal riffs, and psychedelic textures. The trio of Rodrigo Chã (guitar), Manéu Junqueira (bass), and Marcus Dentão (drums) released their self-titled debut in 2011 followed by Badtrip Surfdeath II in 2013, both recorded in São Paulo. Their entirely wordless approach lets the genre-blurring density of the music speak for itself.