Mox Amber (Retro) [The Brothers' War Retro Artifacts] Plains This mana can't be spent

This mana can't be spent to pay generic mana costs

Set: Secret Lair Drop Promos Type: Legendary Creature — Dragon Rarity: Rare Cost: {4}{R}{R}{R} Trample

Set: 30th Anniversary Edition Type: Creature — Elemental Rarity: Uncommon Cost: {3}{R}{R} This version of this card has a non-standard Magic back

Unfortunately

Set: The Lord of the Rings: Tales of Middle-Earth Commander Type: Artifact Rarity: Mythic Cost: {3} Creatures with power greater than the number of cards in your hand can't attack

Mox Amber (Retro) [The Brothers' War Retro Artifacts] Plains This mana can't be spentSet: The Brothers' War Retro Artifacts Type: Legendary Artifact Rarity: Mythic Cost: {0} {T}: Add one mana of any color among legendary creatures and planeswalkers you control. A moment in time made tangible, it has the power to realize epic visions.