Regent's Authority is a common Instant card from Kamigawa: Neon Dynasty (NEO), collector number 32. Current market price: $0.20 (foil $0.24), TCGplayer market prices via Scryfall.
Target creature gets +2/+2 until end of turn. If it's an enchantment creature or legendary creature, instead put a +1/+1 counter on it and it gets +1/+1 until end of turn.