Fledgling Dragon is a uncommon Creature — Dragon card from Modern Horizons 3 (MH3), collector number 280. Current market price: $0.15 (foil $0.29), TCGplayer market prices via Scryfall.
Flying Threshold — As long as there are seven or more cards in your graveyard, this creature gets +3/+3 and has "{R}: This creature gets +1/+0 until end of turn."