Mayael's Aria is a rare Enchantment card from Alara Reborn (ARB), collector number 121. Current market price: $2.24 (foil $9.12), TCGplayer market prices via Scryfall.
At the beginning of your upkeep, put a +1/+1 counter on each creature you control if you control a creature with power 5 or greater. Then you gain 10 life if you control a creature with power 10 or greater. Then you win the game if you control a creature with power 20 or greater.