Hopefully by my submissions below, you’ll get what I’m driving at.
Kiss - Kiss Army
Lady Gaga - little monsters
ICP - Juggalos
Anymore we can add to this list?
Split Enz/Crowded House/Finn Brothers/other projects = Frenz
Midnight Oil = Oilers
Hunters & Collectors/Mark Seymour = Punters
The really obvious one: Grateful Dead = Deadheads.
The Melvens Call a subset of their fanbase Roboheads because back in the day there was a group who would drink a bottle of Robitussin before the show and then mosh their brains out.
Aerosmith = The Blue Army
Phish Heads
Floyd Freaks
Kesha - Animals
Jimmy Buffett has his Parrotheads
The Deadheads and the Parrotheads are the ones that I, an outsider to those fandoms, know about.