Appeal to Eirdu (ECL) from Lorwyn Eclipsed, available at 401 Games Canada.

• Rarity: Common
• Finish: Normal
• Artist: Milivoj Ćeran
• Card Text:
  Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for 1 or one mana of that creature's color.)
  One or two target creatures each get +2/+1 until end of turn.