An audience i think :)
There is no official fan group of offspring.
Barmy Army or Hooligans.
If you mean Justin Bieber fans, they're called "Beliebers".
They're called 'fans'.
They are called Raiders fans.
People at a concert are called several things:crowdaudienceconcertgoersfans
Fans
They're called Blackjacks like a card game, which is also called Twenty-one. Dara fans are called Daralings and CL fans are called CLovers. I'm not sure what Minzy and Bom fans are called.
Dalmatians fans are called "dalmates" =]
After Romeos fans are called the Romeonators or aficiona.
Ed's fans are called Sheerios.