Noble Heritage is a rare Legendary Enchantment — Background card from Battle for Baldur's Gate Promos (PCLB), collector number 35s. Current market price: — (foil $5.41), TCGplayer market prices via Scryfall.
Commander creatures you own have "When this creature enters and at the beginning of your upkeep, each player may put two +1/+1 counters on a creature they control. For each opponent who does, you gain protection from that player until your next turn." (You can't be targeted, dealt damage, or enchanted by anything controlled by that player.)