I don't recall a thread for this being made yet. Anyway, first 20 bands have been announced:
MORBID ANGEL
SAINT VITUS
MORGOTH (Germany)
ANVIL (Canada)
SUFFOCATION
CHURCH OF MISERY (Japan)
DEMIGOD (Finland)
GHOUL
UNSANE
MACABRE
THE DEVIL'S BLOOD (Netherlands)
BETHLEHEM (Germany)
NEGURA BUNGET (Romania)
TODAY IS THE DAY
ULCERATE (New Zealand)
THE DAY EVERYTHING BECAME NOTHING (Australia)
DRAGGED INTO SUNLIGHT (UK)
AGENTS OF ABHORRENCE (Australia)
NAUSEA (California)
BLOODY PHOENIX
MORBID ANGEL
SAINT VITUS
MORGOTH (Germany)
ANVIL (Canada)
SUFFOCATION
CHURCH OF MISERY (Japan)
DEMIGOD (Finland)
GHOUL
UNSANE
MACABRE
THE DEVIL'S BLOOD (Netherlands)
BETHLEHEM (Germany)
NEGURA BUNGET (Romania)
TODAY IS THE DAY
ULCERATE (New Zealand)
THE DAY EVERYTHING BECAME NOTHING (Australia)
DRAGGED INTO SUNLIGHT (UK)
AGENTS OF ABHORRENCE (Australia)
NAUSEA (California)
BLOODY PHOENIX