Primeval Herald is a uncommon Creature — Elf Scout card from Foundations Jumpstart (J25), collector number 702. Current market price: $0.35, TCGplayer market prices via Scryfall.
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.) Whenever this creature enters or attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.