Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Snow-Covered Mountain

Apocalypse Hydra

Apocalypse Hydra enters with X +1/+1 counters on it. If X is 5 or more, it enters with an additional X +1/+1 counters on it.
{1}{R}, Remove a +1/+1 counter from Apocalypse Hydra: It deals 1 damage to any target.

Blood Crypt

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

Hall of Heliod's Generosity

{T}: Add {C}.
{1}{W}, {T}: Put target enchantment card from your graveyard on top of your library.

Temple Garden

({T}: Add {G} or {W}.)
As Temple Garden enters, you may pay 2 life. If you don't, it enters tapped.

The Immortal Sun

Players can't activate planeswalkers' loyalty abilities.
At the beginning of your draw step, draw an additional card.
Spells you cast cost {1} less to cast.
Creatures you control get +1/+1.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Primordial Hydra

Primordial Hydra enters with X +1/+1 counters on it.
At the beginning of your upkeep, double the number of +1/+1 counters on Primordial Hydra.
Primordial Hydra has trample as long as it has ten or more +1/+1 counters on it.

Bayou

Ashnod's Altar

Mirari's Wake

Creatures you control get +1/+1.
Whenever you tap a land for mana, add one mana of any type that land produced.

Badlands

Steam Vents

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

Academy Rector

When Academy Rector dies, you may exile it. If you do, search your library for an enchantment card, put that card onto the battlefield, then shuffle.

Black Sun's Zenith

Put X -1/-1 counters on each creature. Shuffle Black Sun's Zenith into its owner's library.

Secure the Wastes

Create X 1/1 white Warrior creature tokens.

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Mass Manipulation

Gain control of X target creatures and/or planeswalkers.

Tempt with Vengeance

Tempting offer — Create X 1/1 red Elemental creature tokens with haste. Each opponent may create X 1/1 red Elemental creature tokens with haste. For each opponent who does, create X 1/1 red Elemental creature tokens with haste.

Shard Convergence

Search your library for a Plains card, an Island card, a Swamp card, and a Mountain card. Reveal those cards, put them into your hand, then shuffle.

Hunting Wilds

Kicker {3}{G} (You may pay an additional {3}{G} as you cast this spell.)
Search your library for up to two Forest cards, put them onto the battlefield tapped, then shuffle.
If this spell was kicked, untap all Forests put onto the battlefield this way. They become 3/3 green creatures with haste that are still lands.

Thran Dynamo

Voracious Hydra

Trample
Voracious Hydra enters with X +1/+1 counters on it.
When Voracious Hydra enters, choose one —
• Double the number of +1/+1 counters on Voracious Hydra.
• Voracious Hydra fights target creature you don't control.

Gilded Lotus

Mikaeus, the Lunarch

Mikaeus, the Lunarch enters with X +1/+1 counters on it.
{T}: Put a +1/+1 counter on Mikaeus.
{T}, Remove a +1/+1 counter from Mikaeus: Put a +1/+1 counter on each other creature you control.

Hydra Broodmaster

{X}{X}{G}: Monstrosity X. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)
When Hydra Broodmaster becomes monstrous, create X X/X green Hydra creature tokens.

March of the Multitudes

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Create X 1/1 white Soldier creature tokens with lifelink.

Command Tower

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

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

White Sun's Zenith

Create X 2/2 white Cat creature tokens. Shuffle White Sun's Zenith into its owner's library.

Worn Powerstone

Worn Powerstone enters tapped.
{T}: Add {C}{C}.

Tropical Island

Rakdos's Return

Rakdos's Return deals X damage to target opponent or planeswalker. That player or that planeswalker's controller discards X cards.

Scrubland

Underground Sea

Protean Hydra

Protean Hydra enters with X +1/+1 counters on it.
If damage would be dealt to Protean Hydra, prevent that damage and remove that many +1/+1 counters from it.
Whenever a +1/+1 counter is removed from Protean Hydra, put two +1/+1 counters on it at the beginning of the next end step.

Volcanic Island

Snow-Covered Plains

Doubling Cube

{3}, {T}: Double the amount of each type of unspent mana you have.

Steelbane Hydra

Steelbane Hydra enters with X +1/+1 counters on it.
{2}{G}, Remove a +1/+1 counter from Steelbane Hydra: Destroy target artifact or enchantment.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Zendikar Resurgent

Whenever you tap a land for mana, add one mana of any type that land produced. (The types of mana are white, blue, black, red, green, and colorless.)
Whenever you cast a creature spell, draw a card.

Death Wind

Target creature gets -X/-X until end of turn.

Battle at the Bridge

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Target creature gets -X/-X until end of turn. You gain X life.

Killing Wave

For each creature, its controller sacrifices it unless they pay X life.

Snow-Covered Island

Entrancing Melody

Gain control of target creature with mana value X.

Gelatinous Genesis

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Mind Spring

Explosive Vegetation

Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Finale of Glory

Create X 2/2 white Soldier creature tokens with vigilance. If X is 10 or more, also create X 4/4 white Angel creature tokens with flying and vigilance.

Plateau

Mana Confluence

{T}, Pay 1 life: Add one mana of any color.

Oracle of Mul Daya

You may play an additional land on each of your turns.
Play with the top card of your library revealed.
You may play lands from the top of your library.

Entreat the Angels

Create X 4/4 white Angel creature tokens with flying.
Miracle {X}{W}{W} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Hooded Hydra

Hooded Hydra enters with X +1/+1 counters on it.
When Hooded Hydra dies, create a 1/1 green Snake creature token for each +1/+1 counter on it.
Morph {3}{G}{G}
As Hooded Hydra is turned face up, put five +1/+1 counters on it.

Finale of Revelation

Draw X cards. If X is 10 or more, instead shuffle your graveyard into your library, draw X cards, untap up to five lands, and you have no maximum hand size for the rest of the game.
Exile Finale of Revelation.

Animist's Awakening

Reveal the top X cards of your library. Put all land cards from among them onto the battlefield tapped and the rest on the bottom of your library in a random order.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, untap those lands.

Sacred Foundry

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

Altered Ego

This spell can't be countered.
You may have Altered Ego enter as a copy of any creature on the battlefield, except it enters with X additional +1/+1 counters on it.

Taiga

Savageborn Hydra

Double strike
Savageborn Hydra enters with X +1/+1 counters on it.
{1}{R/G}: Put a +1/+1 counter on Savageborn Hydra. Activate only as a sorcery.

Snow-Covered Forest

Stomping Ground

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

Hallowed Fountain

({T}: Add {W} or {U}.)
As Hallowed Fountain enters, you may pay 2 life. If you don't, it enters tapped.

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Curse of the Swine

Exile X target creatures. For each creature exiled this way, its controller creates a 2/2 green Boar creature token.

Godless Shrine

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

Sol Ring

Savage Twister

Savage Twister deals X damage to each creature.

Lifeblood Hydra

Trample
Lifeblood Hydra enters with X +1/+1 counters on it.
When Lifeblood Hydra dies, you gain life and draw cards equal to its power.

Breeding Pool

({T}: Add {G} or {U}.)
As Breeding Pool enters, you may pay 2 life. If you don't, it enters tapped.

Braingeyser

Martial Coup

Create X 1/1 white Soldier creature tokens. If X is 5 or more, destroy all other creatures.

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Unbound Flourishing

Whenever you cast a permanent spell with a mana cost that contains {X}, double the value of X.
Whenever you cast an instant or sorcery spell or activate an ability, if that spell's mana cost or that ability's activation cost contains {X}, copy that spell or ability. You may choose new targets for the copy.

Tundra

Ramos, Dragon Engine

Flying
Whenever you cast a spell, put a +1/+1 counter on Ramos for each of that spell's colors.
Remove five +1/+1 counters from Ramos: Add {W}{W}{U}{U}{B}{B}{R}{R}{G}{G}. Activate only once each turn.

Doubling Season

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Ancient Tomb

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Reflecting Pool

{T}: Add one mana of any type that a land you control could produce.

Hydroid Krasis

When you cast this spell, you gain half X life and draw half X cards. Round down each time.
Flying, trample
Hydroid Krasis enters with X +1/+1 counters on it.

Overgrown Tomb

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

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

Phyrexian Tower

{T}: Add {C}.
{T}, Sacrifice a creature: Add {B}{B}.

Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent of their choice or discards a card.

Snow-Covered Swamp

Finale of Devastation

Search your library and/or graveyard for a creature card with mana value X or less and put it onto the battlefield. If you search your library this way, shuffle. If X is 10 or more, creatures you control get +X/+X and gain haste until end of turn.

Skyshroud Claim

Search your library for up to two Forest cards, put them onto the battlefield, then shuffle.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Savannah

Villainous Wealth

Target opponent exiles the top X cards of their library. You may cast any number of spells with mana value X or less from among them without paying their mana costs.

Watery Grave

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

Field of the Dead

Field of the Dead enters tapped.
{T}: Add {C}.
Whenever Field of the Dead or another land you control enters, if you control seven or more lands with different names, create a 2/2 black Zombie creature token.

Debt to the Deathless

Each opponent loses two times X life. You gain life equal to the life lost this way.

Hungering Hydra

Hungering Hydra enters with X +1/+1 counters on it.
Hungering Hydra can't be blocked by more than one creature.
Whenever Hungering Hydra is dealt damage, put that many +1/+1 counters on it. (It must survive the damage to get the counters.)