A few years ago, Pandora introduced its "Billionaires" program, a way to reward artists who achieved over a billion streams on the service, presenting them with a special plaque, akin to going platinum.
Recently, Pandora announced the launch of Hard Rock Billionaires, a new station honoring hard rock and heavy metal artists who have achieved the honor.
As for the hard rock bands to crack the one billion mark:
Three Days Grace
3 Doors Down
Five Finger Death Punch
The Black Keys
Cage The Elephant
Stream the station here..