Red Mana Battery

{2}, {T}: Put a charge counter on Red Mana Battery.
{T}, Remove any number of charge counters from Red Mana Battery: Add {R}, then add an additional {R} for each charge counter removed this way.

Mirror Universe

{T}, Sacrifice Mirror Universe: Exchange life totals with target opponent. Activate only during your upkeep.

Black Mana Battery

{2}, {T}: Put a charge counter on Black Mana Battery.
{T}, Remove any number of charge counters from Black Mana Battery: Add {B}, then add an additional {B} for each charge counter removed this way.

Life Chisel

Sacrifice a creature: You gain life equal to the sacrificed creature's toughness. Activate only during your upkeep.

Horn of Deafening

{2}, {T}: Prevent all combat damage that would be dealt by target creature this turn.

Triassic Egg

{3}, {T}: Put a hatchling counter on Triassic Egg.
Sacrifice Triassic Egg: Choose one. Activate only if there are two or more hatchling counters on Triassic Egg.
• You may put a creature card from your hand onto the battlefield.
• Return target creature card from your graveyard to the battlefield.

Green Mana Battery

{2}, {T}: Put a charge counter on Green Mana Battery.
{T}, Remove any number of charge counters from Green Mana Battery: Add {G}, then add an additional {G} for each charge counter removed this way.

Blue Mana Battery

{2}, {T}: Put a charge counter on Blue Mana Battery.
{T}, Remove any number of charge counters from Blue Mana Battery: Add {U}, then add an additional {U} for each charge counter removed this way.

Serpent Generator

{4}, {T}: Create a 1/1 colorless Snake artifact creature token. It has "Whenever this creature deals damage to a player, that player gets a poison counter." (A player with ten or more poison counters loses the game.)

Sword of the Ages

Sword of the Ages enters tapped.
{T}, Sacrifice Sword of the Ages and any number of creatures you control: Sword of the Ages deals X damage to any target, where X is the total power of the creatures sacrificed this way, then exile Sword of the Ages and those creature cards.

Mana Matrix

Instant and enchantment spells you cast cost {2} less to cast.

North Star

{4}, {T}: For one spell this turn, you may spend mana as though it were mana of any type to pay that spell's mana cost. (Additional costs are still paid normally.)

Voodoo Doll

At the beginning of your upkeep, put a pin counter on Voodoo Doll.
At the beginning of your end step, if Voodoo Doll is untapped, destroy Voodoo Doll and it deals damage to you equal to the number of pin counters on it.
{X}{X}, {T}: Voodoo Doll deals damage equal to the number of pin counters on it to any target. X is the number of pin counters on Voodoo Doll.

Planar Gate

Creature spells you cast cost {2} less to cast.

Kry Shield

{2}, {T}: Prevent all damage that would be dealt this turn by target creature you control. That creature gets +0/+X until end of turn, where X is its mana value.

Gauntlets of Chaos

{5}, Sacrifice Gauntlets of Chaos: Exchange control of target artifact, creature, or land you control and target permanent an opponent controls that shares one of those types with it. If those permanents are exchanged this way, destroy all Auras attached to them.

Nova Pentacle

{3}, {T}: The next time a source of your choice would deal damage to you this turn, that damage is dealt to target creature of an opponent's choice instead.

Al-abara's Carpet

{5}, {T}: Prevent all damage that would be dealt to you this turn by attacking creatures without flying.

Knowledge Vault

{2}, {T}: Exile the top card of your library face down.
{0}: Sacrifice Knowledge Vault. If you do, discard your hand, then put all cards exiled with Knowledge Vault into their owner's hand.
When Knowledge Vault leaves the battlefield, put all cards exiled with Knowledge Vault into their owner's graveyard.

Life Matrix

{4}, {T}: Put a matrix counter on target creature and that creature gains "Remove a matrix counter from this creature: Regenerate this creature." Activate only during your upkeep.

Arena of the Ancients

Legendary creatures don't untap during their controllers' untap steps.
When Arena of the Ancients enters, tap all legendary creatures.

White Mana Battery

{2}, {T}: Put a charge counter on White Mana Battery.
{T}, Remove any number of charge counters from White Mana Battery: Add {W}, then add an additional {W} for each charge counter removed this way.

Ring of Immortals

{3}, {T}: Counter target instant or Aura spell that targets a permanent you control.

Alchor's Tomb

{2}, {T}: Target permanent you control becomes the color of your choice. (This effect lasts indefinitely.)

Forethought Amulet

At the beginning of your upkeep, sacrifice Forethought Amulet unless you pay {3}.
If an instant or sorcery source would deal 3 or more damage to you, it deals 2 damage to you instead.