Blood Crypt

({T}: Add {B} or {R}.)
As Blood Crypt enters, you may pay 2 life. If you don't, it enters tapped.

Bloodstained Mire

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

Mountain

Cavern of Souls

As Cavern of Souls enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

Caldera Breaker

Trample
When Caldera Breaker enters, exile all Mountain cards from your library. When you do, Caldera Breaker deals that much damage to target creature or planeswalker an opponent controls.
When Caldera Breaker dies, put all cards exiled with it onto the battlefield under their owner's control. Conjure four cards named Volcanic Geyser into your library, then shuffle.

Geothermal Bog

({T}: Add {B} or {R}.)
Geothermal Bog enters tapped.

Prismatic Vista

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

Corrupted Conviction

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Swamp

Sulfurous Mire

({T}: Add {B} or {R}.)
Sulfurous Mire enters tapped.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Gate to Tumbledown

Gate to Tumbledown enters tapped.
{3}{R}, {T}: Seek a nonland card. Activate only once.
{T}: Add {R}.

Smoldering Marsh

({T}: Add {B} or {R}.)
Smoldering Marsh enters tapped unless you control two or more basic lands.

Canyon Slough

({T}: Add {B} or {R}.)
Canyon Slough enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

Polluted Delta

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Raucous Theater

({T}: Add {B} or {R}.)
Raucous Theater enters tapped.
When Raucous Theater enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Crucias, Titan of the Waves

At the beginning of your end step, you may discard a card. If you do, create a Treasure token and choose ambitious or expedient. If you chose ambitious, seek a card with greater mana value than the discarded card. If you chose expedient, seek a card with lesser mana value than the discarded card.