Solitary Sanctuary is a uncommon Enchantment card from Wilds of Eldraine (WOE), collector number 30. Current market price: $0.30 (foil $0.34), TCGplayer market prices via Scryfall.
When this enchantment enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.) Whenever you tap an untapped creature an opponent controls, put a +1/+1 counter on target creature you control.