Acid Angel was a thrash metal band from São Bernardo do Campo, in the greater São Paulo metropolitan area of Brazil, formed in 1989 and active through the mid-1990s before splitting up. Operating as an independent underground act, the band was part of the wave of Brazilian thrash that flourished in São Paulo's industrial satellite cities during the late 1980s and early 1990s.

Acid Blood is a thrash metal band from Brasília, Distrito Federal, Brazil, active in the capital's relatively compact but dedicated underground metal scene. The band operates independently, delivering straight-ahead thrash metal that draws on the classic Brazilian and international thrash traditions cultivated since the 1980s.

Acid Brigade was a thrash metal band from Londrina, Paraná, Brazil, active from 2016 to around 2019. They released the demo "Addiction to Distortion" in 2016 and followed it with their full-length "Storming Into This Land" in 2019, a record tracked at Toque Grave Estúdio and noted for its palm-muted riffing and old-school new-wave-of-thrash energy.

Acid Evil is a one-woman Thrash Metal act from Quito, Ecuador, active since 2009 with the same member handling all instruments and vocals throughout the band's existence. The project released its debut demo Black Space in 2010 and full-length Multidimensional Past in 2019, signing with Triple Goddess Recs for the 2024 EP Saturnian Kult.

Acid Storm is a thrash metal band from São Paulo with roots stretching back to 1986, when they operated under the name Exterminator in the city's northern suburbs before reforming under the current name in 1989. Their second album, Biotronic Genesis (1991), is regarded as a classic of Brazilian technical thrash metal, drawing comparisons to Testament and Forbidden with sci-fi and warfare lyrical themes. The band reunited in 2020 and continues to carry the torch of São Paulo's veteran underground thrash scene.

Acrostic are a thrash metal band from Viña del Mar who describe their sound as "Noisethrash" — a blend of old-school thrash, hardcore punk, and crust rooted in the Bay Area and European thrash traditions. The trio of Janito Attack, Pablito Attack, and Pelao Attack released their full-length "Sincretismo-Posguerra" in November 2016 on Underground Defenders Records, a 11-track record recorded at JRP Studios in Viña del Mar and limited to 500 copies.

Age Nor Defields is a crossover thrash quintet from Mongaguá, on the São Paulo state coast of Brazil, fusing thrash metal with hardcore punk energy and grindcore experimentation. Their album "Mongahell" is a 25-minute barrage of politically charged, anti-fascist material delivered in Portuguese, mixing protest and class consciousness with acid humor and absurdist provocation. Reviewers have noted their earnest, exuberant approach and the Zappa-esque tendency to wrap pointed social commentary in comedic delivery.

Aggresion is a death/thrash metal band from Campo Grande, Mato Grosso do Sul, formed in 2012 and operating as a power trio with Eduardo Sparrenberger on vocals and bass, Caverna on guitar, and Felipe TerrorDeath on drums. Their 2024 album Covil de Feras, recorded at Estudio 45 in Campo Grande, leans into Brazilian folklore and indigenous resistance as lyrical themes, pairing them with a raw, satanic extreme metal aesthetic. The band contributed to underground anti-fascist metal compilations in 2018 and 2019.

Aggression Tales are a thrash metal band from São Paulo founded in 2006 by guitarist Felipe Ruiz alongside vocalist/bassist Bruno Pompeo and drummer Julio Príncipe. Their 2007 debut Scribbles in Blood is a concept album narrating the life of a fictional serial killer, with each of its twelve tracks written in collaboration with ten different fiction authors who each penned a chapter of the story. They followed it with Random Acts of Physical Disgust (2011) on Six Inch Nails Records, cementing a sharp, aggressive thrash attack with a dark literary bent.