Horizon Stone

If you would lose unspent mana, that mana becomes colorless instead.

Shizuko, Caller of Autumn

At the beginning of each player's upkeep, that player adds {G}{G}{G}. Until end of turn, they don't lose this mana as steps and phases end.

New Frontiers

Each player may search their library for up to X basic land cards and put them onto the battlefield tapped. Then each player who searched their library this way shuffles.

Seedborn Muse

Untap all permanents you control during each other player's untap step.

Helm of Awakening

Yurlok of Scorch Thrash

Vigilance
A player losing unspent mana causes that player to lose that much life.
{1}, {T}: Each player adds {B}{R}{G}.

Heartbeat of Spring

Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

Ghirapur Orrery

Each player may play an additional land on each of their turns.
At the beginning of each player's upkeep, if that player has no cards in hand, that player draws three cards.

Hunted Wumpus

When this creature enters, each other player may put a creature card from their hand onto the battlefield.

Tempting Contract

At the beginning of your upkeep, each opponent may create a Treasure token. For each opponent who does, you create a Treasure token.

Power Surge

At the beginning of each player's upkeep, this enchantment deals X damage to that player, where X is the number of untapped lands they controlled at the beginning of this turn.

Heartwood Storyteller

Whenever a player casts a noncreature spell, each of that player's opponents may draw a card.

Humble Defector

{T}: Draw two cards. Target opponent gains control of this creature. Activate only during your turn.

Citadel of Pain

At the beginning of each player's end step, this enchantment deals X damage to that player, where X is the number of untapped lands they control.

Umbral Mantle

Equipped creature has "{3}, {Q}: This creature gets +2/+2 until end of turn." ({Q} is the untap symbol.)
Equip {0}

Tempting Wurm

When this creature enters, each opponent may put any number of artifact, creature, enchantment, and/or land cards from their hand onto the battlefield.

Mana Flare

Keeper of Progenitus

Whenever a player taps a Mountain, Forest, or Plains for mana, that player adds one mana of any type that land produced.

Staff of Domination

{1}: Untap this artifact.
{2}, {T}: You gain 1 life.
{3}, {T}: Untap target creature.
{4}, {T}: Tap target creature.
{5}, {T}: Draw a card.

Howling Mine

At the beginning of each player's draw step, if this artifact is untapped, that player draws an additional card.

Pir's Whim

For each player, choose friend or foe. Each friend searches their library for a land card, puts it onto the battlefield tapped, then shuffles. Each foe sacrifices an artifact or enchantment of their choice.

Magus of the Candelabra

Dictate of Karametra

Flash
Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

Zhur-Taa Ancient

Boldwyr Heavyweights

Trample
When this creature enters, each opponent may search their library for a creature card and put it onto the battlefield. Then each player who searched their library this way shuffles.

Scrawling Crawler

At the beginning of your upkeep, each player draws a card.
Whenever an opponent draws a card, that player loses 1 life.

Overabundance

Whenever a player taps a land for mana, that player adds one mana of any type that land produced, and this enchantment deals 1 damage to the player.

Prevent all combat damage that would be dealt this turn.

Barbflare Gremlin

First strike, haste
Whenever a player taps a land for mana, if this creature is tapped, that player adds one mana of any type that land produced. Then that land deals 1 damage to that player.

Vernal Equinox

Any player may cast creature and enchantment spells as though they had flash.

Otherworld Atlas

{T}: Put a charge counter on this artifact.
{T}: Each player draws a card for each charge counter on this artifact.

Avatar of Growth

This spell costs {1} less to cast for each opponent you have.
Trample
When this creature enters, each player searches their library for up to two basic land cards, puts them onto the battlefield, then shuffles.

Belbe, Corrupted Observer

At the beginning of each postcombat main phase, the active player adds {C}{C} for each of your opponents who lost life this turn. (Damage causes loss of life.)

Manabarbs

Whenever a player taps a land for mana, this enchantment deals 1 damage to that player.

Magus of the Vineyard

At the beginning of each player's first main phase, that player adds {G}{G}.

Stoneshaker Shaman

At the beginning of each player's end step, that player sacrifices an untapped land of their choice.