Roots of Primer 55

Helmet is an American alternative metal band from New York City formed in 1989 by vocalist and lead guitarist Page Hamilton. Helmet has had numerous lineup changes with Hamilton as the only constant member. Since 2010, the band has consisted of Hamilton, drummer Kyle Stevenson, guitarist Dan Beeman and bassist Dave Case.

Skrape was an American nu metal band formed in Orlando, Florida in 1997. They released two albums, New Killer America (2001) and Up the Dose (2004), before disbanding in 2004 and briefly reuniting in 2005. After twenty-one years of inactivity, the band are currently attempting to reform in 2026 pending the outcome of a legal challenge to vocalist Billy Keeton's use of the band's name.

Slipknot is an American heavy metal band formed in Des Moines, Iowa, in 1995 by percussionist Shawn Crahan, vocalist Anders Colsefni and bassist Paul Gray. After several lineup changes in its early years, the band settled on nine members from 1999 until Gray's death in 2010: Crahan, Gray, Joey Jordison, Craig Jones, Mick Thomson, Corey Taylor, Sid Wilson, Chris Fehn, and Jim Root. Slipknot is well known for its attention-grabbing image, aggressive style of music, and energetic and chaotic live shows.

Machine Head is an American heavy metal band from Oakland, California. The band was formed in 1991 by vocalist/guitarist Robb Flynn, who remains the only original member of the band. Machine Head's aggressive musicianship made it one of the pioneering bands in the new wave of American heavy metal. Its current lineup comprises Flynn, bassist Jared MacEachern, drummer Matt Alston and guitarist Reece Scruggs. Bassist Adam Duce, guitarists Logan Mader, Ahrue Luster, Phil Demmel and Wacław Kiełtyka, and drummers Tony Costanza, Chris Kontos and Dave McClain are former members of the band; Mader and Kontos toured with the band in 2019 and 2020 as part of the 25th anniversary tour for its first album, Burn My Eyes (1994).

Dope is an American industrial metal band from New York City, formed in 1997. The band has released seven full-length studio albums with their most recent studio album, Blood Money Part Zer0, being released in February 2023. The lineup currently consists of founding member and lead singer, rhythm guitarist and keyboardist Edsel Dope, lead guitarist Virus, bassist Acey Slade, and drummer Daniel Fox. As of 2022, they have sold over one million albums worldwide.

Soulfly is a Brazilian-American heavy metal band formed in Phoenix, Arizona in 1997. Soulfly is led by former Sepultura frontman Max Cavalera, who formed the band after he left the Brazilian group in 1996. To date the band has released thirteen studio albums, one tour EP, twenty-three singles, one video album, and twelve music videos. Their debut album, Soulfly, was released on April 21, 1998, while their most recent album, Chama, was released in October 2025.

2 Live Crew is an American hip-hop group from Miami, Florida, formed in 1984. The group was originally composed of DJ Mr. Mixx, Fresh Kid Ice, and Amazing Vee. However, its most well-known lineup emerged later with the addition of Brother Marquis and the replacement of Amazing Vee by Luther "Luke Skyywalker" Campbell, who also served as the group's manager and promoter. Known for their provocative lyrics and sexually explicit content, 2 Live Crew gained widespread attention in the late 1980s and early 1990s, becoming pioneers of the Miami bass genre and influential figures in the development of Southern hip hop. Their breakthrough album, The 2 Live Crew Is What We Are (1986), introduced their signature sound, blending booming basslines with humorous and risqué themes.

Twiztid is an American hip hop duo from Detroit, Michigan, known for both their horror-themed lyrics and rock-influenced sound. Formed in 1997, Twiztid is composed of rappers Jamie "Madrox" Spaniolo and Paul "Monoxide" Methric. Spaniolo and Methric are also members of the group House of Krazees with Bryan "The R.O.C." Jones, which formed in 1992.

Korn is an American nu metal band from Bakersfield, California, originally formed in 1993 by James "Munky" Shaffer, Reginald "Fieldy" Arvizu and David Silveria, who were members of the band L.A.P.D. Their current lineup features Shaffer (guitar), Brian "Head" Welch (guitar), Jonathan Davis (vocals), and Ray Luzier (drums), the last of whom replaced Silveria in 2007. The band is notable for pioneering and popularizing the nu metal genre.