Your search for "Jet Medallion 292" revealed the following:
Jet Medallion (MH3) from Modern Horizons 3, available at 401 Games Canada. Rarity: Rare Finish: Normal Artist: Daniel Ljunggren Card Text:Black spells you cast cost 1 less to cast.
Jet Medallion (Foil) (MH3) from Modern Horizons 3, available at 401 Games Canada. Rarity: Rare Finish: Foil Artist: Daniel Ljunggren Card Text:Black spells you cast cost 1 less to cast.
Jet Medallion - TMP Reprint (PLST) from The List, available at 401 Games Canada. Rarity: Rare Finish: Normal Artist: Sue Ellen Brown Card Text:Your black spells cost 1 less to play.
Jet Medallion (TMP) from Tempest, available at 401 Games Canada. Rarity: Rare Finish: Normal Artist: Sue Ellen Brown Card Text:Your black spells cost 1 less to play.
Jet Medallion (Etched) (CMM) from Commander Masters, available at 401 Games Canada. Rarity: Rare Finish: Foil Artist: Daniel Ljunggren Card Text:Black spells you cast cost 1 less to cast.