Legion Vanguard is a uncommon Creature — Vampire Soldier card from Jumpstart: Historic Horizons (J21), collector number 345.
{1}, Sacrifice another creature: This creature explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)