Your search for "Unbreathing Horde 121" revealed the following:
Unbreathing Horde (ISD) from Innistrad, available at 401 Games Canada. Rarity: Rare Finish: Normal Artist: Dave Kendall Card Text:Unbreathing Horde enters the battlefield with a +1/+1 counter on it for each other Zombie you control and for each Zombie card...
Unbreathing Horde (Foil) (ISD) from Innistrad, available at 401 Games Canada. Rarity: Rare Finish: Foil Artist: Dave Kendall Card Text:Unbreathing Horde enters the battlefield with a +1/+1 counter on it for each other Zombie you control and for each Zombie...
Unbreathing Horde (DDQ) from Duel Decks: Blessed vs. Cursed, available at 401 Games Canada. Rarity: Rare Finish: Normal Artist: Dave Kendall Card Text:Unbreathing Horde enters the battlefield with a +1/+1 counter on it for each other Zombie you control and...
Unbreathing Horde (SCD) from Starter Commander Decks, available at 401 Games Canada. Rarity: Rare Finish: Normal Artist: Dave Kendall Card Text:Unbreathing Horde enters the battlefield with a +1/+1 counter on it for each other Zombie you control and each Zombie...