Dirtwater Wraith

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
{B}: Dirtwater Wraith gets +1/+0 until end of turn.

Blanket of Night

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

Scoured Barrens

Scoured Barrens enters the battlefield tapped.
When Scoured Barrens enters the battlefield, you gain 1 life.
{T}: Add {W} or {B}.

Urborg, Tomb of Yawgmoth

Korlash, Heir to Blackblade

Korlash, Heir to Blackblade's power and toughness are each equal to the number of Swamps you control.
{1}{B}: Regenerate Korlash.
Grandeur — Discard another card named Korlash, Heir to Blackblade: Search your library for up to two Swamp cards, put them onto the battlefield tapped, then shuffle.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Crusading Knight

Protection from black
Crusading Knight gets +1/+1 for each Swamp your opponents control.

Wrexial, the Risen Deep

Islandwalk, swampwalk (This creature can't be blocked as long as defending player controls an Island or a Swamp.)
Whenever Wrexial, the Risen Deep deals combat damage to a player, you may cast target instant or sorcery card from that player's graveyard without paying its mana cost. If that spell would be put into a graveyard, exile it instead.

Traveler's Cloak

Enchant creature
As Traveler's Cloak enters the battlefield, choose a land type.
When Traveler's Cloak enters the battlefield, draw a card.
Enchanted creature has landwalk of the chosen type. (It can't be blocked as long as defending player controls a land of that type.)

Whispering Shade

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
{B}: Whispering Shade gets +1/+1 until end of turn.

Custodi Lich

When Custodi Lich enters the battlefield, you become the monarch.
Whenever you become the monarch, target player sacrifices a creature.

Knights of the Black Rose

When Knights of the Black Rose enters the battlefield, you become the monarch.
Whenever an opponent becomes the monarch, if you were the monarch as the turn began, that player loses 2 life and you gain 2 life.

Coastal Tower

Coastal Tower enters the battlefield tapped.
{T}: Add {W} or {U}.

Command Tower

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

Burnished Hart

{3}, Sacrifice Burnished Hart: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Dromar's Cavern

When Dromar's Cavern enters the battlefield, sacrifice it unless you return a non-Lair land you control to its owner's hand.
{T}: Add {W}, {U}, or {B}.

Auramancer

When Auramancer enters the battlefield, you may return target enchantment card from your graveyard to your hand.

Opportunity

Return to Dust

Exile target artifact or enchantment. If you cast this spell during your main phase, you may exile up to one other target artifact or enchantment.

Orzhov Basilica

Orzhov Basilica enters the battlefield tapped.
When Orzhov Basilica enters the battlefield, return a land you control to its owner's hand.
{T}: Add {W}{B}.

Kor Cartographer

When Kor Cartographer enters the battlefield, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle.

Sword of the Animist

Equipped creature gets +1/+1.
Whenever equipped creature attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Equip {2}

Mismatched

Swamp

Temple of Silence

Temple of Silence enters the battlefield tapped.
When Temple of Silence enters the battlefield, scry 1.
{T}: Add {W} or {B}.

Dismal Backwater

Dismal Backwater enters the battlefield tapped.
When Dismal Backwater enters the battlefield, you gain 1 life.
{T}: Add {U} or {B}.

Purity

Flying
If noncombat damage would be dealt to you, prevent that damage. You gain life equal to the damage prevented this way.
When Purity is put into a graveyard from anywhere, shuffle it into its owner's library.

Liliana of the Dark Realms

+1: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.
−3: Target creature gets +X/+X or -X/-X until end of turn, where X is the number of Swamps you control.
−6: You get an emblem with "Swamps you control have '{T}: Add {B}{B}{B}{B}.'"

Vow of Duty

Enchant creature
Enchanted creature gets +2/+2, has vigilance, and can't attack you or planeswalkers you control.

Journeyer's Kite

{3}, {T}: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Selfless Squire

Flash
When Selfless Squire enters the battlefield, prevent all damage that would be dealt to you this turn.
Whenever damage that would be dealt to you is prevented, put that many +1/+1 counters on Selfless Squire.

Solemn Simulacrum

When Solemn Simulacrum enters the battlefield, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When Solemn Simulacrum dies, you may draw a card.

Realmwright

As Realmwright enters the battlefield, choose a basic land type.
Lands you control are the chosen type in addition to their other types.

Meandering River

Meandering River enters the battlefield tapped.
{T}: Add {W} or {U}.

Quag Sickness

Enchant creature
Enchanted creature gets -1/-1 for each Swamp you control.

Bojuka Bog

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

Duelist's Heritage

Whenever one or more creatures attack, you may have target attacking creature gain double strike until end of turn.

Filth

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
As long as Filth is in your graveyard and you control a Swamp, creatures you control have swampwalk.

Expedition Map

{2}, {T}, Sacrifice Expedition Map: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Magus of the Coffers

{2}, {T}: Add {B} for each Swamp you control.

Crystal Chimes

{3}, {T}, Sacrifice Crystal Chimes: Return all enchantment cards from your graveyard to your hand.

Nightmare

Flying (This creature can't be blocked except by creatures with flying or reach.)
Nightmare's power and toughness are each equal to the number of Swamps you control.

Dakmor Sorceress

Dakmor Sorceress's power is equal to the number of Swamps you control.

Sol Ring

Island

Karma

At the beginning of each player's upkeep, Karma deals damage to that player equal to the number of Swamps they control.

Tendrils of Corruption

Tendrils of Corruption deals X damage to target creature and you gain X life, where X is the number of Swamps you control.

Tolaria West

Tolaria West enters the battlefield tapped.
{T}: Add {U}.
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with mana value 0, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Sima Yi, Wei Field Marshal

Sima Yi, Wei Field Marshal's power is equal to the number of Swamps you control.

Royal Decree

Cumulative upkeep {W} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever a Swamp, Mountain, black permanent, or red permanent becomes tapped, Royal Decree deals 1 damage to that permanent's controller.

Prahv, Spires of Order

{T}: Add {C}.
{4}{W}{U}, {T}: Prevent all damage a source of your choice would deal this turn.

Hanna, Ship's Navigator

{1}{W}{U}, {T}: Return target artifact or enchantment card from your graveyard to your hand.

Vow of Malice

Enchant creature
Enchanted creature gets +2/+2, has intimidate, and can't attack you or planeswalkers you control. (A creature with intimidate can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Plains

Prairie Stream

({T}: Add {W} or {U}.)
Prairie Stream enters the battlefield tapped unless you control two or more basic lands.

Angry Mob

Trample
As long as it's your turn, Angry Mob's power and toughness are each equal to 2 plus the number of Swamps your opponents control. As long as it's not your turn, Angry Mob's power and toughness are each 2.

Magosi, the Waterveil

Magosi, the Waterveil enters the battlefield tapped.
{T}: Add {U}.
{U}, {T}: Put an eon counter on Magosi, the Waterveil. Skip your next turn.
{T}, Remove an eon counter from Magosi, the Waterveil and return it to its owner's hand: Take an extra turn after this one.

Zur the Enchanter

Flying
Whenever Zur the Enchanter attacks, you may search your library for an enchantment card with mana value 3 or less, put it onto the battlefield, then shuffle.

Dakkon Blackblade

Dakkon Blackblade's power and toughness are each equal to the number of lands you control.

Imprisoned in the Moon

Enchant creature, land, or planeswalker
Enchanted permanent is a colorless land with "{T}: Add {C}" and loses all other card types and abilities.

Tidings

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Tranquil Cove

Tranquil Cove enters the battlefield tapped.
When Tranquil Cove enters the battlefield, you gain 1 life.
{T}: Add {W} or {U}.

Dimir Aqueduct

Dimir Aqueduct enters the battlefield tapped.
When Dimir Aqueduct enters the battlefield, return a land you control to its owner's hand.
{T}: Add {U}{B}.

Propaganda

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

Vault of the Archangel

{T}: Add {C}.
{2}{W}{B}, {T}: Creatures you control gain deathtouch and lifelink until end of turn.

Temple of Enlightenment

Temple of Enlightenment enters the battlefield tapped.
When Temple of Enlightenment enters the battlefield, scry 1.
{T}: Add {W} or {U}.

Lashwrithe

Living weapon (When this Equipment enters the battlefield, create a 0/0 black Phyrexian Germ creature token, then attach this to it.)
Equipped creature gets +1/+1 for each Swamp you control.
Equip {B/P}{B/P} ({B/P} can be paid with either {B} or 2 life.)

Mutilate

All creatures get -1/-1 until end of turn for each Swamp you control.

Spectral Grasp

Enchant creature
Enchanted creature can't attack you or planeswalkers you control.
Enchanted creature can't block creatures you control.

Temple of Deceit

Temple of Deceit enters the battlefield tapped.
When Temple of Deceit enters the battlefield, scry 1.
{T}: Add {U} or {B}.

Arcane Sanctum

Arcane Sanctum enters the battlefield tapped.
{T}: Add {W}, {U}, or {B}.

Submerged Boneyard

Submerged Boneyard enters the battlefield tapped.
{T}: Add {U} or {B}.

Vow of Flight

Enchant creature
Enchanted creature gets +2/+2, has flying, and can't attack you or planeswalkers you control.

Ghostly Prison

Corrupt

Corrupt deals damage to any target equal to the number of Swamps you control. You gain life equal to the damage dealt this way.

Darksteel Ingot

Indestructible (Effects that say "destroy" don't destroy this artifact.)
{T}: Add one mana of any color.

Nightmare Lash

Equipped creature gets +1/+1 for each Swamp you control.
Equip—Pay 3 life. (Pay 3 life: Attach to target creature you control. Equip only as a sorcery. This card enters the battlefield unattached and stays on the battlefield if the creature leaves.)

Surveyor's Scope

{T}, Exile Surveyor's Scope: Search your library for up to X basic land cards, where X is the number of players who control at least two more lands than you. Put those cards onto the battlefield, then shuffle.

Thalia's Lancers

First strike
When Thalia's Lancers enters the battlefield, you may search your library for a legendary card, reveal it, put it into your hand, then shuffle.

Stern Judge

{T}: Each player loses 1 life for each Swamp they control.

Shielded by Faith

Enchant creature
Enchanted creature has indestructible.
Whenever a creature enters the battlefield, you may attach Shielded by Faith to that creature.

Squelching Leeches

Squelching Leeches's power and toughness are each equal to the number of Swamps you control.

Crypt Ghast

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.)
Whenever you tap a Swamp for mana, add an additional {B}.

Oath of Lieges

At the beginning of each player's upkeep, that player chooses target player who controls more lands than they do and is their opponent. The first player may search their library for a basic land card, put that card onto the battlefield, then shuffle.

Personal Sanctuary

During your turn, prevent all damage that would be dealt to you.

Azorius Chancery

Azorius Chancery enters the battlefield tapped.
When Azorius Chancery enters the battlefield, return a land you control to its owner's hand.
{T}: Add {W}{U}.