Infected Mind was a death/thrash metal band from Campina Grande, Paraíba, Brazil, signed to the InfernalFox label. The band recorded their album "Rascals of Destruction" at Ponto Som Studio in Campina Grande, which includes a live bonus track — a cover of Black Sabbath's "Into the Void." Their lyrical themes centered on social issues and injustice.

Infernal Atröz is a black/thrash metal band from Blumenau, Santa Catarina, Brazil, formed in 2022 and rooted in Satanic themes. The band released a debut single-demo in January 2023, followed by the track "A Noite da Caçada" and a full demo in 2024. They operate as an unsigned independent act within southern Brazil's underground extreme metal scene.

Infernal Hate is a thrash metal band from Ijuí, Rio Grande do Sul, Brazil with a long-running presence in the country's underground metal scene. The band's discography includes the full-length Upset (2008) and the demo ...See Me Come (2022), both catalogued in the Encyclopaedia Metallum. They remain active as an independent act within Brazil's southern thrash metal underground.

Inferno Nuclear is an old-school thrash metal band from Belém, Pará, Brazil, formed in 2007 under the name Old School Attack before adopting their current name. Drawing heavily from the Bay Area and German thrash traditions — citing Exodus, Testament, Kreator, and Sodom as key influences — the band features vocalist Wellington Freitas alongside rotating members including guitarist Alexandre Durães. Their 2021 album Diante de um Holocausto was recorded at Chaar Estúdio in Belém and stands as one of their most fully produced releases.

Infestatio is a thrash metal quartet from Jundiaí, São Paulo, Brazil, featuring Rafael "Rafão" Neves on guitars and vocals, Reginaldo "Regi" Iobbi on guitars, Diego "Negão" Necromancer on bass, and André "Fanta" on drums. The band blends old-school and modern thrash approaches with groove-driven riffs and semi-aggressive vocals that draw comparisons to acts like Sadus. Their EP F.Y.A., a five-track release produced by Rafão and recorded partly at Jardim Elétrico Studios, drew favorable coverage from Brazilian metal press on its release.

Insanity was a death/thrash metal band from Fortaleza, Ceará, Brazil, formed in 1989 under the name HON (Hexistence of Noise) by bassist/vocalist George Frizzo and guitarist Alberto Lopes before adopting the Insanity name later that year. The band released the demo "In Search of Reason" in 1990, recorded at Proaudio Studios in Fortaleza, and later issued the full-length "Phobia" in 1993 through Muvuca Records before splitting up in 2003.

Insecticida is an old-school thrash metal band from Timbaúba, Pernambuco, Brazil, playing aggressive 1980s-style thrash with no modern frills. The band infuses northeastern Brazilian culture into their music, including humorous lyrics that tackle social themes with regional irony, and released their debut EP "Deu a Mulesta dos Cachorro" in 2017.

Insomnio Mutante is a thrash metal band from Chillán, Chile, active since 1998. They released their debut album Mundo Desconocido in May 2014, recorded at Estudios Decibeles between September 2013 and March 2014.

Insulter was a Brazilian death/thrash metal band from Belo Horizonte, Minas Gerais, formed in 2012, working in the same extreme underground tradition as early local acts like Sarcófago and Sextrash. Their demo recordings were compiled and released in 2015 by Nuclear War Now! Productions on the album "Blood Spits, Violences and Insults," which also appeared on Iron Bonehead Productions in a gatefold LP edition.