Detroit-area punk forerunners MC5 became eligible for induction in 1991. They were previously nominated in 2003.
Rock & Roll Hall of Fame bio:
"With their politically insurgent rhetoric and culture-shredding ideologies, Detroit rockers the Motor City Five—also known as the MC5—embodied the late '60s societal and musical revolutions. Musically, the quintet was just as inflammatory: The group's inimitable combo of fiery, blues- and R&B-influenced proto-punk—as heard on albums such as 1969's Kick Out The Jams—has influenced everyone from Black Flag to Rage Against The Machine."