Valiant Veteran is a rare Creature — Kor Soldier card from Dominaria United Promos (PDMU), collector number 38p. Current market price: $1.28 (foil $0.74), TCGplayer market prices via Scryfall.
Other Soldiers you control get +1/+1. {3}{W}{W}, Exile this card from your graveyard: Put a +1/+1 counter on each Soldier you control.