Godsmack
Metallica
A Life Once Lost
Disturbed x 2
Drowning Pool
System of a Down
The Mars Volta
Red Hot Chili Peppers
Gnarls Barkley
Rob Zombie
Mudvayne
Slipknot
Bury Your Dead
Damageplan
SOiL
As I Lay Dying x 2
Anthrax
God Forbid
Soilwork
Trivium
The Black Dahlia Murder
Killswitch Engage
Mastadon
Black Label Society
Shadows Fall
Ten Years
Iron Maiden
Black Sabbath

Thats pretty much the well known list.. there are some other warm up bands and ozzfest bands that aren't too well known. Out of those I've been able to get guitar picks from System of a Down, Damageplan, and Bury Your Dead. I had a friend get a drum cover from As I Lay Dying once.. was pretty cool.