Your search for "Plains 309" revealed the following:
Plains - Showcase (M21) from Core Set 2021, available at 401 Games Canada. Rarity: Common Finish: Normal Artist: Jonas De Ro
Plains (009) (PELP) from European Land Program, available at 401 Games Canada. Rarity: Common Finish: Normal Artist: Eric Peterson
Plains - Showcase (Foil) (M21) from Core Set 2021, available at 401 Games Canada. Rarity: Common Finish: Foil Artist: Jonas De Ro
Plains (039) (DDI) from Duel Decks: Venser vs. Koth, available at 401 Games Canada. Rarity: Common Finish: Normal Artist: James Paick