Your search for "Mossfire Valley 250" revealed the following:
Mossfire Valley (CLB) from Commander Legends: Battle for Baldur's Gate, available at 401 Games Canada. Rarity: Rare Finish: Normal Artist: Yeong-Hao Han Card Text:1, T: Add RG.
Mossfire Valley (AFC) from Forgotten Realms Commander, available at 401 Games Canada. Rarity: Rare Finish: Normal Artist: Yeong-Hao Han Card Text:1, T: Add RG.
Mossfire Valley (Foil) (ODY) from Odyssey, available at 401 Games Canada. Rarity: Rare Finish: Foil Artist: John Avon Card Text:1, T: Add RG to your mana pool.