Mountain

Niv-Mizzet, Parun

This spell can't be countered.
Flying
Whenever you draw a card, Niv-Mizzet deals 1 damage to any target.
Whenever a player casts an instant or sorcery spell, you draw a card.

Oppression

Whenever a player casts a spell, that player discards a card.

Ichneumon Druid

Whenever an opponent casts an instant spell other than the first instant spell that player casts each turn, this creature deals 4 damage to that player.

Mayhem Devil

Whenever a player sacrifices a permanent, this creature deals 1 damage to any target.

Verdant Catacombs

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

Polluted Delta

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

Isolation Cell

Whenever an opponent casts a creature spell, that player loses 2 life unless they pay {2}.

Dimir Signet

Misty Rainforest

{T}, Pay 1 life, Sacrifice this land: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

Forgotten Ancient

Whenever a player casts a spell, you may put a +1/+1 counter on this creature.
At the beginning of your upkeep, you may move any number of +1/+1 counters from this creature onto other creatures.

Insight

Whenever an opponent casts a green spell, you draw a card.

Mind's Eye

Whenever an opponent draws a card, you may pay {1}. If you do, draw a card.

Raiders' Wake

Whenever an opponent discards a card, that player loses 2 life.
Raid — At the beginning of your end step, if you attacked this turn, target opponent discards a card.

Sandsteppe Citadel

This land enters tapped.
{T}: Add {W}, {B}, or {G}.

Chimeric Egg

Whenever an opponent casts a nonartifact spell, put a charge counter on this artifact.
Remove three charge counters from this artifact: This artifact becomes a 6/6 Construct artifact creature with trample until end of turn.

Fate Unraveler

Whenever an opponent draws a card, this creature deals 1 damage to that player.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Heartwood Storyteller

Whenever a player casts a noncreature spell, each of that player's opponents may draw a card.

Forest

Frontier Bivouac

This land enters tapped.
{T}: Add {G}, {U}, or {R}.

Golos, Tireless Pilgrim

When Golos, Tireless Pilgrim enters, you may search your library for a land card, put that card onto the battlefield tapped, then shuffle.
{2}{W}{U}{B}{R}{G}: Exile the top three cards of your library. You may play them this turn without paying their mana costs.

Runic Armasaur

Whenever an opponent activates an ability of a creature or land that isn't a mana ability, you may draw a card.

Reparations

Whenever an opponent casts a spell that targets you or a creature you control, you may draw a card.

Golgari Signet

Mazirek, Kraul Death Priest

Flying
Whenever a player sacrifices another permanent, put a +1/+1 counter on each creature you control.

Savai Triome

({T}: Add {R}, {W}, or {B}.)
This land enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Azorius Signet

Izzet Signet

Ob Nixilis, the Hate-Twisted

Whenever an opponent draws a card, Ob Nixilis deals 1 damage to that player.
−2: Destroy target creature. Its controller draws two cards.

Orzhov Signet

Xyris, the Writhing Storm

Flying
Whenever an opponent draws a card except the first one they draw in each of their draw steps, create a 1/1 green Snake creature token.
Whenever Xyris deals combat damage to a player, you and that player each draw that many cards.

Paradise Plume

As this artifact enters, choose a color.
Whenever a player casts a spell of the chosen color, you may gain 1 life.
{T}: Add one mana of the chosen color.

Indatha Triome

({T}: Add {W}, {B}, or {G}.)
This land enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Burgeoning

Whenever an opponent plays a land, you may put a land card from your hand onto the battlefield.

Mold Adder

Whenever an opponent casts a blue or black spell, you may put a +1/+1 counter on this creature.

Kaervek the Merciless

Whenever an opponent casts a spell, Kaervek deals damage equal to that spell's mana value to any target.

Kraken's Eye

Whenever a player casts a blue spell, you may gain 1 life.

Command Tower

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

Arcane Signet

Seaside Citadel

This land enters tapped.
{T}: Add {G}, {W}, or {U}.

Liliana's Caress

Whenever an opponent discards a card, that player loses 2 life.

Memory Erosion

Whenever an opponent casts a spell, that player mills two cards.

Kavu Predator

Trample
Whenever an opponent gains life, put that many +1/+1 counters on this creature.

Dragon's Claw

Whenever a player casts a red spell, you may gain 1 life.

Angel's Feather

Whenever a player casts a white spell, you may gain 1 life.

Taurean Mauler

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on this creature.

Arid Mesa

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

Marsh Flats

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

Island

Citanul Druid

Whenever an opponent casts an artifact spell, put a +1/+1 counter on this creature.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice this artifact: Draw a card.

Kor Firewalker

Protection from red
Whenever a player casts a red spell, you may gain 1 life.

Ketria Triome

({T}: Add {G}, {U}, or {R}.)
This land enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Sanctimony

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

Arasta of the Endless Web

Reach
Whenever an opponent casts an instant or sorcery spell, create a 1/2 green Spider creature token with reach.

Savage Lands

This land enters tapped.
{T}: Add {B}, {R}, or {G}.

Raugrin Triome

({T}: Add {U}, {R}, or {W}.)
This land enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Immolation Shaman

Whenever an opponent activates an ability of an artifact, creature, or land that isn't a mana ability, this creature deals 1 damage to that player.
{3}{R}{R}: This creature gets +3/+3 and gains menace until end of turn.

Harsh Mentor

Whenever an opponent activates an ability of an artifact, creature, or land on the battlefield, if it isn't a mana ability, this creature deals 2 damage to that player.

Swamp

Ruric Thar, the Unbowed

Vigilance, reach
Ruric Thar attacks each combat if able.
Whenever a player casts a noncreature spell, Ruric Thar deals 6 damage to that player.

Dragonlair Spider

Reach
Whenever an opponent casts a spell, create a 1/1 green Insect creature token.

Wooded Foothills

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

Arcane Sanctum

This land enters tapped.
{T}: Add {W}, {U}, or {B}.

Zagoth Triome

({T}: Add {B}, {G}, or {U}.)
This land enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Deep-Sea Kraken

This creature can't be blocked.
Suspend 9—{2}{U} (Rather than cast this card from your hand, you may pay {2}{U} and exile it with nine time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)
Whenever an opponent casts a spell, if this card is suspended, remove a time counter from it.

Infested Roothold

Defender (This creature can't attack.)
Protection from artifacts
Whenever an opponent casts an artifact spell, you may create a 1/1 green Insect creature token.

Crumbling Necropolis

This land enters tapped.
{T}: Add {U}, {B}, or {R}.

Confessor

Whenever a player discards a card, you may gain 1 life.

Soldier of the Pantheon

Protection from multicolored
Whenever an opponent casts a multicolored spell, you gain 1 life.

Warmth

Whenever an opponent casts a red spell, you gain 2 life.

Lurking Predators

Whenever an opponent casts a spell, reveal the top card of your library. If it's a creature card, put it onto the battlefield. Otherwise, you may put that card on the bottom of your library.

Plains

Chromatic Lantern

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

Forced Fruition

Whenever an opponent casts a spell, that player draws seven cards.

Painful Quandary

Whenever an opponent casts a spell, that player loses 5 life unless they discard a card.

Consecrated Sphinx

Flying
Whenever an opponent draws a card, you may draw two cards.

Opulent Palace

This land enters tapped.
{T}: Add {B}, {G}, or {U}.

Ob Nixilis, Unshackled

Flying, trample
Whenever an opponent searches their library, that player sacrifices a creature of their choice and loses 10 life.
Whenever another creature dies, put a +1/+1 counter on Ob Nixilis.

Thraximundar

Haste
Whenever Thraximundar attacks, defending player sacrifices a creature of their choice.
Whenever a player sacrifices a creature, you may put a +1/+1 counter on Thraximundar.

Golem's Heart

Whenever a player casts an artifact spell, you may gain 1 life.

Selesnya Signet

Nezahal, Primal Tide

This spell can't be countered.
You have no maximum hand size.
Whenever an opponent casts a noncreature spell, draw a card.
Discard three cards: Exile Nezahal. Return it to the battlefield tapped under its owner's control at the beginning of the next end step.

Ishai, Ojutai Dragonspeaker

Flying
Whenever an opponent casts a spell, put a +1/+1 counter on Ishai.
Partner (You can have two commanders if both have partner.)

Snake Pit

Whenever an opponent casts a blue or black spell, you may create a 1/1 green Snake creature token.

Boros Signet

Pain Magnification

Whenever an opponent is dealt 3 or more damage by a single source, that player discards a card.

Nath of the Gilt-Leaf

At the beginning of your upkeep, you may have target opponent discard a card at random.
Whenever an opponent discards a card, you may create a 1/1 green Elf Warrior creature token.

Mindcrank

Whenever an opponent loses life, that player mills that many cards. (Damage causes loss of life.)

Rewards of Diversity

Whenever an opponent casts a multicolored spell, you gain 4 life.

Geth's Grimoire

Whenever an opponent discards a card, you may draw a card.

Wurm's Tooth

Whenever a player casts a green spell, you may gain 1 life.

River Kelpie

Whenever this creature or another permanent enters from a graveyard, draw a card.
Whenever a player casts a spell from a graveyard, draw a card.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Underworld Dreams

Whenever an opponent draws a card, this enchantment deals 1 damage to that player.

Soul Barrier

Whenever an opponent casts a creature spell, this enchantment deals 2 damage to that player unless they pay {2}.

Noosegraf Mob

This creature enters with five +1/+1 counters on it.
Whenever a player casts a spell, remove a +1/+1 counter from this creature. If you do, create a 2/2 black Zombie creature token.

Jungle Shrine

This land enters tapped.
{T}: Add {R}, {G}, or {W}.

Total War

Whenever a player attacks with one or more creatures, destroy all untapped non-Wall creatures that player controls that didn't attack, except for creatures the player hasn't controlled continuously since the beginning of the turn.

Gruul Signet

Cosi's Trickster

Whenever an opponent shuffles their library, you may put a +1/+1 counter on this creature.

Sunscorch Regent

Flying
Whenever an opponent casts a spell, put a +1/+1 counter on this creature and you gain 1 life.

Cindervines

Whenever an opponent casts a noncreature spell, this enchantment deals 1 damage to that player.
{1}, Sacrifice this enchantment: Destroy target artifact or enchantment. This enchantment deals 2 damage to that permanent's controller.

Hunting Grounds

Threshold — As long as seven or more cards are in your graveyard, this enchantment has "Whenever an opponent casts a spell, you may put a creature card from your hand onto the battlefield."

Kambal, Consul of Allocation

Whenever an opponent casts a noncreature spell, that player loses 2 life and you gain 2 life.

Bloodstained Mire

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

Windswept Heath

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

Havoc

Whenever an opponent casts a white spell, they lose 2 life.