Nykthos Paragon is a rare Enchantment Creature — Human Soldier card from Modern Horizons 2 (MH2), collector number 331. Current market price: $0.94 (foil $0.91), TCGplayer market prices via Scryfall.
Whenever you gain life, you may put that many +1/+1 counters on each creature you control. Do this only once each turn.