Guardian Shield-Bearer is a common Creature — Human Soldier card from The List (PLST), collector number DTK-189. Current market price: $0.10, TCGplayer market prices via Scryfall.
Megamorph {3}{G} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.) When this creature is turned face up, put a +1/+1 counter on another target creature you control.