Ghalta, Stampede Tyrant

Trample
When Ghalta enters, put any number of creature cards from your hand onto the battlefield.

Farseek

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

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.

Spelltithe Enforcer

Whenever an opponent casts a spell, that player sacrifices a permanent of their choice unless they pay {1}.

Painful Quandary

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

Kambal, Consul of Allocation

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

Scrubland

Sheoldred, the Apocalypse

Deathtouch
Whenever you draw a card, you gain 2 life.
Whenever an opponent draws a card, they lose 2 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.

Plateau

Chancellor of the Annex

You may reveal this card from your opening hand. If you do, when each opponent casts their first spell of the game, counter that spell unless that player pays {1}.
Flying
Whenever an opponent casts a spell, counter it unless that player pays {1}.

Tundra

Nyxbloom Ancient

Trample
If you tap a permanent for mana, it produces three times as much of that mana instead.

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.

Isolation Cell

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

Kraum, Ludevic's Opus

Flying, haste
Whenever an opponent casts their second spell each turn, draw a card.
Partner (You can have two commanders if both have partner.)

Consecrated Sphinx

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

Savannah

Forced Fruition

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

Plains

Tropical Island

Steam Clean

Return target nonland permanent to its owner's hand. (Then exile this card. You may cast the creature later from exile.)

Scalding Viper

Whenever an opponent casts a spell with mana value 3 or less, this creature deals 1 damage to that player.

Scalding Viper // Steam Clean

Burgeoning

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

Underground Sea

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.

Lavinia, Azorius Renegade

Each opponent can't cast noncreature spells with mana value greater than the number of lands that player controls.
Whenever an opponent casts a spell, if no mana was spent to cast it, counter that spell.

Powerbalance

Whenever an opponent casts a spell, you may reveal the top card of your library. If you do, you may cast that card without paying its mana cost if the two spells have the same mana value.

Archivist of Oghma

Flash
Whenever an opponent searches their library, you gain 1 life and draw a card.

Mountain

Kaervek the Merciless

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

Mind's Dilation

Whenever an opponent casts their first spell each turn, that player exiles the top card of their library. If it's a nonland card, you may cast it without paying its mana cost.

Exquisite Blood

Whenever an opponent loses life, you gain that much life.

Dragonlair Spider

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

Fell Specter

Flying
When this creature enters, target opponent discards a card.
Whenever an opponent discards a card, that player loses 2 life.

Lulu, Stern Guardian

Whenever an opponent attacks you, choose target creature attacking you. Put a stun counter on that creature.
{3}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Bayou

The Prismatic Bridge

At the beginning of your upkeep, reveal cards from the top of your library until you reveal a creature or planeswalker card. Put that card onto the battlefield and the rest on the bottom of your library in a random order.

Esika, God of the Tree

Vigilance
{T}: Add one mana of any color.
Other legendary creatures you control have vigilance and "{T}: Add one mana of any color."

Esika, God of the Tree // The Prismatic Bridge

Cunning Rhetoric

Whenever an opponent attacks you and/or one or more planeswalkers you control, exile the top card of that player's library. You may play that card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast it.

Tergrid's Lantern

{T}: Target player loses 3 life unless they sacrifice a nonland permanent of their choice or discard a card.
{3}{B}: Untap Tergrid's Lantern.

Tergrid, God of Fright

Menace
Whenever an opponent sacrifices a nontoken permanent or discards a permanent card, you may put that card from a graveyard onto the battlefield under your control.

Tergrid, God of Fright // Tergrid's Lantern

Command Tower

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

Legate Lanius, Caesar's Ace

Decimate — When Legate Lanius enters, each opponent sacrifices a tenth of the creatures they control of their choice, rounded up.
Whenever an opponent sacrifices a creature, put a +1/+1 counter on Legate Lanius.

Malik, Grim Manipulator

When Malik, Grim Manipulator enters, you and target opponent each secretly choose a creature that player controls. Then those choices are revealed, and that player sacrifices those creatures.
Whenever an opponent sacrifices a creature, you create a Treasure token.

Forest

Sanctimony

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

Mage Hunter

Whenever an opponent casts or copies an instant or sorcery spell, they lose 1 life.

Psychic Surgery

Whenever an opponent shuffles their library, you may look at the top two cards of that library. You may exile one of those cards. Then put the rest on top of that library in any order.

Whip of Erebos

Creatures you control have lifelink.
{2}{B}{B}, {T}: Return target creature card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step. If it would leave the battlefield, exile it instead of putting it anywhere else. Activate only as a sorcery.

March of the World Ooze

Creatures you control have base power and toughness 6/6 and are Oozes in addition to their other types.
Whenever an opponent casts a spell, if it's not their turn, you create a 3/3 green Elephant creature token.

Mindcrank

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

Aether Sting

Whenever an opponent casts a creature spell, this enchantment deals 1 damage to that player.

Nazgûl Battle-Mace

Equipped creature has menace, deathtouch, annihilator 1, and "Whenever an opponent sacrifices a nontoken permanent, put that card onto the battlefield under your control unless that player pays 3 life." (Whenever a creature with annihilator 1 attacks, defending player sacrifices a permanent of their choice.)
Equip {3}

Nekusar, the Mindrazer

At the beginning of each player's draw step, that player draws an additional card.
Whenever an opponent draws a card, Nekusar deals 1 damage to that player.

Bloodthirsty Conqueror

Flying, deathtouch
Whenever an opponent loses life, you gain that much life. (Damage causes loss of life.)

Hunting Grounds

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

Badlands

Vorinclex, Voice of Hunger

Trample
Whenever you tap a land for mana, add one mana of any type that land produced.
Whenever an opponent taps a land for mana, that land doesn't untap during its controller's next untap step.

Chromatic Orrery

You may spend mana as though it were mana of any color.
{T}: Add {C}{C}{C}{C}{C}.
{5}, {T}: Draw a card for each color among permanents you control.

Liliana's Caress

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

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.

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

It That Betrays

Annihilator 2 (Whenever this creature attacks, defending player sacrifices two permanents of their choice.)
Whenever an opponent sacrifices a nontoken permanent, put that card onto the battlefield under your control.

Megrim

Whenever an opponent discards a card, this enchantment deals 2 damage to that player.

Swamp

Island

Taiga

Bloodroot Apothecary

Toxic 2 (Players dealt combat damage by this creature also get two poison counters. A player with ten or more poison counters loses the game.)
When this creature enters, you and target opponent each create a Treasure token.
Whenever an opponent sacrifices a noncreature token, that player gets two poison counters.

Sauron, the Dark Lord

Ward—Sacrifice a legendary artifact or legendary creature.
Whenever an opponent casts a spell, amass Orcs 1.
Whenever an Army you control deals combat damage to a player, the Ring tempts you.
Whenever the Ring tempts you, you may discard your hand. If you do, draw four cards.

Fate Unraveler

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

Volcanic Island

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

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 token: Add one mana of any color.")

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.

Memory Erosion

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

Skyshroud Claim

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

Gleeful Arsonist

Whenever an opponent casts a noncreature spell, this creature deals damage equal to its power to that player.
Undying (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.)

Cultivate

Scrawling Crawler

At the beginning of your upkeep, each player draws a card.
Whenever an opponent draws a card, that player loses 1 life.