Orcish Farmer

{T}: Target land becomes a Swamp until its controller's next untap step.

Scald

Whenever a player taps an Island for mana, Scald deals 1 damage to that player.

Volcanic Eruption

Destroy X target Mountains. Volcanic Eruption deals damage to each creature and each player equal to the number of Mountains put into a graveyard this way.

Thelon's Chant

At the beginning of your upkeep, sacrifice Thelon's Chant unless you pay {G}.
Whenever a player puts a Swamp onto the battlefield, Thelon's Chant deals 3 damage to that player unless the player puts a -1/-1 counter on a creature they control.

Stormtide Leviathan

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
All lands are Islands in addition to their other types.
Creatures without flying or islandwalk can't attack.

Stench of Evil

Destroy all Plains. For each land destroyed this way, Stench of Evil deals 1 damage to that land's controller unless they pay {2}.

Corrupted Roots

Enchant Forest or Plains
Whenever enchanted land becomes tapped, its controller loses 2 life.

Waiting in the Weeds

Each player creates a 1/1 green Cat creature token for each untapped Forest they control.

Lifetap

Whenever a Forest an opponent controls becomes tapped, you gain 1 life.

Bubbling Muck

Until end of turn, whenever a player taps a Swamp for mana, that player adds an additional {B}.

Active Volcano

Choose one —
• Destroy target blue permanent.
• Return target Island to its owner's hand.

Tundra Kavu

{T}: Target land becomes a Plains or an Island until end of turn.

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.

Thoughtleech

Whenever an Island an opponent controls becomes tapped, you may gain 1 life.

Raiding Party

Raiding Party can't be the target of white spells or abilities from white sources.
Sacrifice an Orc: Each player may tap any number of untapped white creatures they control. For each creature tapped this way, that player chooses up to two Plains. Then destroy all Plains that weren't chosen this way by any player.

Tourach's Chant

At the beginning of your upkeep, sacrifice Tourach's Chant unless you pay {B}.
Whenever a player puts a Forest onto the battlefield, Tourach's Chant deals 3 damage to that player unless they put a -1/-1 counter on a creature they control.

War Barge

{3}: Target creature gains islandwalk until end of turn. When War Barge leaves the battlefield this turn, destroy that creature. A creature destroyed this way can't be regenerated. (A creature with islandwalk can't be blocked as long as defending player controls an Island.)

Kavu Recluse

{T}: Target land becomes a Forest until end of turn.

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.

Choke

Islands don't untap during their controllers' untap steps.

Nightcreep

Until end of turn, all creatures become black and all lands become Swamps.

Quarum Trench Gnomes

{T}: If target Plains is tapped for mana, it produces colorless mana instead of white mana. (This effect lasts indefinitely.)

Renewing Dawn

You gain 2 life for each Mountain target opponent controls.

Glacial Crevasses

Sacrifice a snow Mountain: Prevent all combat damage that would be dealt this turn.

Reign of Chaos

Choose one —
• Destroy target Plains and target white creature.
• Destroy target Island and target blue creature.

Carpet of Flowers

At the beginning of each of your main phases, if you haven't added mana with this ability this turn, you may add X mana of any one color, where X is the number of Islands target opponent controls.

Volcanic Strength

Enchant creature
Enchanted creature gets +2/+2 and has mountainwalk. (It can't be blocked as long as defending player controls a Mountain.)

Veldrane of Sengir

{1}{B}{B}: Veldrane of Sengir gets -3/-0 and gains forestwalk until end of turn. (It can't be blocked as long as defending player controls a Forest.)

Boggart Loggers

Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)
{2}{B}, Sacrifice Boggart Loggers: Destroy target Treefolk or Forest.

Child of Alara

Trample
When Child of Alara dies, destroy all nonland permanents. They can't be regenerated.

Blood Moon

Lifeblood

Whenever a Mountain an opponent controls becomes tapped, you gain 1 life.

Desolation

At the beginning of each end step, each player who tapped a land for mana this turn sacrifices a land. Desolation deals 2 damage to each player who sacrificed a Plains this way.

Urborg, Tomb of Yawgmoth

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

Crusading Knight

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

Blanket of Night

Naked Singularity

Cumulative upkeep {3} (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.)
If tapped for mana, Plains produce {R}, Islands produce {G}, Swamps produce {W}, Mountains produce {U}, and Forests produce {B} instead of any other type.

Baleful Stare

Target opponent reveals their hand. You draw a card for each Mountain and red card in it.

Fruition

You gain 1 life for each Forest on the battlefield.

Drought

At the beginning of your upkeep, sacrifice Drought unless you pay {W}{W}.
Spells cost an additional "Sacrifice a Swamp" to cast for each black mana symbol in their mana costs.
Activated abilities cost an additional "Sacrifice a Swamp" to activate for each black mana symbol in their activation costs.

Thelon's Curse

Blue creatures don't untap during their controllers' untap steps.
At the beginning of each player's upkeep, that player may choose any number of tapped blue creatures they control and pay {U} for each creature chosen this way. If the player does, untap those creatures.

Kormus Bell

All Swamps are 1/1 black creatures that are still lands.

Pulverize

You may sacrifice two Mountains rather than pay this spell's mana cost.
Destroy all artifacts.

Withering Gaze

Target opponent reveals their hand. You draw a card for each Forest and green card in it.

Karma

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

Roots of Life

As Roots of Life enters the battlefield, choose Island or Swamp.
Whenever a land of the chosen type an opponent controls becomes tapped, you gain 1 life.

Flashfires

Cyclopean Tomb

{2}, {T}: Put a mire counter on target non-Swamp land. That land is a Swamp for as long as it has a mire counter on it. Activate only during your upkeep.
When Cyclopean Tomb is put into a graveyard from the battlefield, at the beginning of each of your upkeeps for the rest of the game, remove all mire counters from a land that a mire counter was put onto with Cyclopean Tomb but that a mire counter has not been removed from with Cyclopean Tomb.

Lumbering Satyr

All creatures have forestwalk. (They can't be blocked as long as defending player controls a Forest.)

Sandals of Abdallah

{2}, {T}: Target creature gains islandwalk until end of turn. When that creature dies this turn, destroy Sandals of Abdallah. (A creature with islandwalk can't be blocked as long as defending player controls an Island.)

Sanctimony

Whenever an opponent taps a Mountain for mana, you may gain 1 life.

Monsoon

At the beginning of each player's end step, tap all untapped Islands that player controls and Monsoon deals X damage to the player, where X is the number of Islands tapped this way.

Yavimaya, Cradle of Growth

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

Acid Rain

Typhoon

Typhoon deals damage to each opponent equal to the number of Islands that player controls.

Stern Judge

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

Flash Flood

Choose one —
• Destroy target red permanent.
• Return target Mountain to its owner's hand.