Your search for "mountain 306" revealed the following:
Mountain (302) (MRD) from Mirrodin, available at 401 Games Canada. Rarity: Common Finish: Normal Artist: John Avon
Mountain (300) (CHK) from Champions of Kamigawa, available at 401 Games Canada. Rarity: Common Finish: Normal Artist: John Avon
Forest (306) (MRD) from Mirrodin, available at 401 Games Canada. Rarity: Common Finish: Normal Artist: John Avon
Leona - Radiant Dawn (Signature) - 306*/298 - Showcase from Riftbound: Origins, available at 401 Games Canada. Rarity: Showcase Finish: Foil Artist: Su Ke Card Text:When you stun one or more enemy units, buff a friendly unit. (If it doesn't...
Eevee (Japanese) - 306/SM-P - Promo from SM-P: Sun & Moon Promos, available at 401 Games Canada. Rarity: Promo Finish: Holofoil Artist: Kagemaru Himeno Card Text:[Colorless] CuriosityYour opponent reveals their hand.[Colorless][Colorless] Spin Tackle (30)Flip a coin. If tails, this Pokémon...