Crested Sunmare is a mythic Creature — Horse card from Secret Lair Drop (SLD), collector number 1228. Current market price: $18.03 (foil $19.45), TCGplayer market prices via Scryfall.
Other Horses you control have indestructible. At the beginning of each end step, if you gained life this turn, create a 5/5 white Horse creature token.