Cloud of Darkness {2}{B}{G}{G}
Legendary Creature — Avatar
Identity
Golgari
EDHREC rank
#17,086
Cheapest printing
US$0.15
TCGplayer
Printings
2
Flying
Particle Beam — When Cloud of Darkness enters, target creature an opponent controls gets -X/-X until end of turn, where X is the number of permanent cards in your graveyard.
Keywords: particle beam, flying
Every printing
highest TCGplayer market first; a card with only a thin single listing shows its low
In short
A Commander deck is a commander and 99 other cards, one copy of each (except basic lands), all inside the commander's colour identity. Paste a full list into the deck price calculator to price it and check it against the format.