Aderiva is a crossover heavy metal band from Fortaleza, Ceará, Brazil, blending hardcore and heavy metal in a style rooted in the northeastern Brazilian underground rock scene. Active since 1999 in various forms and revived under the Aderiva name around 2015–2016, the band released the EP "Vida Longa e Próspera" in 2016 and the full-length "Auto Evolução", the latter celebrating 20 years of the group's history.

Adriano Arguelho is a shred and heavy metal guitarist from Campo Grande, Mato Grosso do Sul, Brazil, operating as a solo project since 2022. Drawing on the tradition of Brazilian instrumental guitar, the project emphasizes technical, high-speed fretwork rooted in heavy metal.

Age of Fear is a heavy metal band from Paulo Afonso, in the interior of Bahia, Brazil, formed in 2014. One of the few metal acts from this small city in the São Francisco Valley, the band operates in the classic heavy metal tradition and has released material including a self-titled EP, a demo "Echoes of a Lost Age," and the album "Born in Darkness." Their existence reflects the spread of Brazil's metal underground well beyond the major urban centers of São Paulo and Rio de Janeiro.

Ahura Mazda is a traditional heavy metal band from Pouso Alegre, Minas Gerais, with roots stretching back to 1992 before reforming in their current incarnation around 2012. The band features a twin-guitar lineup and recorded a demo in 1994, drawing on classic heavy metal influences while operating as an independent act in the Minas Gerais underground.

AISA are a heavy metal and hard rock band from Santiago formed in 2019 by Julio Soto (bassist of SteelRage and DarkSpell) alongside vocalist Eva Murgas (of Beerhalla). The band debuted with the single "Let Us Rock" in November 2019 and released their full-length album "Join Me to Metal" in 2022, a 10-track record issued on CD in a limited edition of 300 copies.

Aizen is a classic heavy metal band from Rosario, Argentina, drawing on the sounds of Judas Priest, Scorpions, and early hard rock. The band released their debut demo in 2020, recorded at Studio Paramo in Rosario, and contributed the track "Warrior Through Time" to the Argentine compilation Nueva ola del heavy metal Argentino in 2021. The current lineup features Gabi Franc on lead guitar and vocals, Guillermo Luna on bass, and Lautaro Trevisan on drums.

Alakran is a Buenos Aires heavy metal and hard rock band with roots going back to 1982, making them one of Argentina's longest-running acts in the genre. Founded by guitarist Gady Pampillón and vocalist Mario Curcio, the band released albums including Vagabundear and Otra vez en las calles (1991), and has since continued under vocalist Mario Ian through multiple reunion periods. They were part of the wave of Argentine hard rock acts — alongside Kamikaze and Rata Blanca — that defined the sound of the country's metal scene in the late 1980s.

Aleacion was a heavy metal band from San Juan, Argentina, active through the 1990s under the name Cromagnon before adopting the Aleacion name. The band released the EP "El combatiente" in 1995 and documented their live performances on the 1996 release "Vivos en el Auditorio Juan Victoria".

Alianza was a Buenos Aires heavy metal project formed by vocalist Adrián Barilari and keyboardist Hugo Bistolfi following their departure from Rata Blanca in the early 1990s. The duo released three albums — "Sueños del Mundo" (1994), "Alianza" (1997), and "Huellas" (1999) — blending melodic heavy metal with the symphonic keyboard work that defined Bistolfi's style.