Stonybrook Banneret is a common Creature — Merfolk Wizard card from Morningtide (MOR), collector number 51. Current market price: $0.88 (foil $24.60), TCGplayer market prices via Scryfall.
Islandwalk (This creature can't be blocked as long as defending player controls an Island.) Merfolk spells and Wizard spells you cast cost {1} less to cast.