First Sliver's Chosen is a uncommon Creature — Sliver card from Modern Horizons (MH1), collector number 9. Current market price: $0.22 (foil $1.33), TCGplayer market prices via Scryfall.
Sliver creatures you control have exalted. (Whenever a creature you control attacks alone, it gets +1/+1 until end of turn for each instance of exalted among permanents you control.)