Forerunner of the Legion is a uncommon Creature — Vampire Knight card from Rivals of Ixalan (RIX), collector number 9. Current market price: $1.18 (foil $7.82), TCGplayer market prices via Scryfall.
When this creature enters, you may search your library for a Vampire card, reveal it, then shuffle and put that card on top. Whenever another Vampire you control enters, target creature gets +1/+1 until end of turn.