Grimoire of the Dead
Legendary Artifact
, 
, Discard a card: Put a study counter on Grimoire of the Dead.
, Remove three study counters from Grimoire of the Dead and sacrifice it: Put all creature cards from all graveyards onto the battlefield under your control. They're black Zombies in addition to their other colors and types.
Steven Belledin
Commander 2019 (C19)
• #213Rulings
“Creature cards” includes each card with the type creature, even if it has additional types, such as artifact.
(wotc • 2011-09-22)
Rulings
“Creature cards” includes each card with the type creature, even if it has additional types, such as artifact.
(wotc • 2011-09-22)