Crucible of Worlds

Retreat to Emeria

Landfall — Whenever a land you control enters, choose one —
• Create a 1/1 white Kor Ally creature token.
• Creatures you control get +1/+1 until end of turn.

Valakut Exploration

Landfall — Whenever a land you control enters, exile the top card of your library. You may play that card for as long as it remains exiled.
At the beginning of your end step, if there are cards exiled with Valakut Exploration, put them into their owner's graveyard, then Valakut Exploration deals that much damage to each opponent.

Land Tax

At the beginning of your upkeep, if an opponent controls more lands than you, you may search your library for up to three basic land cards, reveal them, put them into your hand, then shuffle.

Nahiri's Lithoforming

Sacrifice X lands. For each land sacrificed this way, draw a card. You may play X additional lands this turn. Lands you control enter tapped this turn.

Trove Warden

Vigilance
Landfall — Whenever a land you control enters, exile target permanent card with mana value 3 or less from your graveyard.
When Trove Warden dies, put each permanent card exiled with it onto the battlefield under the control of that card's owner.

Red Elemental Blast

Choose one —
• Counter target blue spell.
• Destroy target blue permanent.

Felidar Retreat

Landfall — Whenever a land you control enters, choose one —
• Create a 2/2 white Cat Beast creature token.
• Put a +1/+1 counter on each creature you control. Those creatures gain vigilance until end of turn.

Walking Atlas

{T}: You may put a land card from your hand onto the battlefield.

Arid Mesa

{T}, Pay 1 life, Sacrifice Arid Mesa: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.

Ghen, Arcanum Weaver

{R}{W}{B}, {T}, Sacrifice an enchantment: Return target enchantment card from your graveyard to the battlefield.

Aura of Silence

Artifact and enchantment spells your opponents cast cost {2} more to cast.
Sacrifice Aura of Silence: Destroy target artifact or enchantment.

Ghostly Prison

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Fabled Passage

{T}, Sacrifice Fabled Passage: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Heliod, Sun-Crowned

Indestructible
As long as your devotion to white is less than five, Heliod isn't a creature.
Whenever you gain life, put a +1/+1 counter on target creature or enchantment you control.
{1}{W}: Another target creature gains lifelink until end of turn.

Goblin Trenches

{2}, Sacrifice a land: Create two 1/1 red and white Goblin Soldier creature tokens.

Marsh Flats

{T}, Pay 1 life, Sacrifice Marsh Flats: Search your library for a Plains or Swamp card, put it onto the battlefield, then shuffle.

Tithe

Search your library for a Plains card. If target opponent controls more lands than you, you may search your library for an additional Plains card. Reveal those cards, put them into your hand, then shuffle.

Prismatic Vista

{T}, Pay 1 life, Sacrifice Prismatic Vista: Search your library for a basic land card, put it onto the battlefield, then shuffle.

Blind Obedience

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Artifacts and creatures your opponents control enter tapped.