A Day to Fall is a groove metal and melodic death metal project formed in 2011 with Argentine musicians, releasing the album Architects of Hate along with tracks such as Southern Flame and What Lies Ahead. The band blends melodeath intensity with metalcore-driven heaviness, drawing on the members' roots in the Argentine underground scene.

A.R.I.D.A. is a groove metal and metalcore band from San Rafael, Mendoza, formed by vocalist and bassist Francisco Escudero, guitarists Tomas Villegas and Alejandro Martin, and drummer Mariana Gutierrez. The band released their debut album Sueño Demencial in May 2022, a five-track conceptual record produced with support from Argentina's INAMU arts funding program.

Alkimistal is a São Paulo-based metal act working the intersection of melodic death metal, thrash, and metalcore. Their Bandcamp release 'Reflections' showcases the blend of harsh riffing and melodic hooks that defines their sound within São Paulo's underground scene.

All Belong to Us is a metalcore band from Santa Cruz de la Sierra, Bolivia, whose lineup has included vocalists, dual guitarists, bass, and drums across their recorded output. They have released the EP First of All, the single Inmortalized, and the full-length Before the Darkness Comes, establishing themselves as one of the few metalcore acts in the Bolivian underground scene.

Antropos is a Brazilian groove metal and metalcore band formed in 2020, blending the heavy mid-tempo rhythms and chugging riffs of groove metal with the melodic structures and dynamic range characteristic of metalcore. Active within Brazil's contemporary underground scene, the band represents the country's ongoing absorption and reinterpretation of international heavy subgenres through a distinctly South American lens. They distribute their music independently through Bandcamp.

Asense is a progressive death metal and metalcore band from Santiago, Chile, formed in 2009, whose discography spans three albums: "The Cold Nightmares of Belphegor: Tempest in Seven Regions" (2009), "Cellarius" (2014), and "tō kyō - o da i ba" (2018). Their lyrics address sociopolitical themes and complex philosophical ideas, and all three records are available independently on Bandcamp.

Atria was a thrash metal and metalcore band from Maricá, Rio de Janeiro state, formed in 2020 and short-lived. Blending the riff aggression of thrash with metalcore's structured heaviness, the band were part of the broader metal underground in the greater Rio de Janeiro region before disbanding.

Atrocitus is a thrash and metalcore band from Curitiba, Paraná, one of the more active names in the city's underground metal scene. Drawing on aggressive thrash structures alongside metalcore dynamics, the three-piece — featuring Huan Cruz on vocals and bass, Geert Giullian Strijker on guitar, and Pettrus on drums — has released singles such as "Veneno" and "Repulsa" and built a following through energetic live shows across the Paraná metal circuit.

Aversus formed in 2012 in Centenario, Neuquén, blending metalcore aggression with thrash metal riffing in a corner of Patagonia that has produced only a handful of extreme acts. The band is signed to Marfus' Records, a Neuquén-based label dedicated to thrash, death, and metalcore from the region.