Concerted Effort is a rare Enchantment card from Ravnica: City of Guilds (RAV), collector number 8. Current market price: $7.12 (foil $12.22), TCGplayer market prices via Scryfall.
At the beginning of each upkeep, creatures you control gain flying until end of turn if a creature you control has flying. The same is true for fear, first strike, double strike, landwalk, protection, trample, and vigilance.