Opposition Agent

Flash
You control your opponents while they're searching their libraries.
While an opponent is searching their library, they exile each card they find. You may play those cards for as long as they remain exiled, and you may spend mana as though it were mana of any color to cast them.

Dauthi Voidwalker

Shadow (This creature can block or be blocked by only creatures with shadow.)
If a card would be put into an opponent's graveyard from anywhere, instead exile it with a void counter on it.
{T}, Sacrifice Dauthi Voidwalker: Choose an exiled card an opponent owns with a void counter on it. You may play it this turn without paying its mana cost.

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. Adarkar Wastes deals 1 damage to you.

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.)

Praetor's Grasp

Search target opponent's library for a card and exile it face down. Then that player shuffles. You may play that card for as long as it remains exiled.

Badlands

Underground Sea

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Preordain

Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

City of Brass

Whenever City of Brass becomes tapped, it deals 1 damage to you.
{T}: Add one mana of any color.

Arid Mesa

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

Paladin Class

(Gain the next level as a sorcery to add its ability.)
Spells your opponents cast during your turn cost {1} more to cast.
{2}{W}: Level 2
Creatures you control get +1/+1.
{4}{W}: Level 3
Whenever you attack, until end of turn, target attacking creature gets +1/+1 for each other attacking creature and gains double strike.

Watery Grave

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

Ranger-Captain of Eos

When Ranger-Captain of Eos enters, you may search your library for a creature card with mana value 1 or less, reveal it, put it into your hand, then shuffle.
Sacrifice Ranger-Captain of Eos: Your opponents can't cast noncreature spells this turn.

Mental Misstep

({U/P} can be paid with either {U} or 2 life.)
Counter target spell with mana value 1.

Deafening Silence

Each player can't cast more than one noncreature spell each turn.

Sea of Clouds

Sea of Clouds enters tapped unless you have two or more opponents.
{T}: Add {W} or {U}.

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.

Hushwing Gryff

Flash
Flying
Creatures entering don't cause abilities to trigger.

Deflecting Swat

If you control a commander, you may cast this spell without paying its mana cost.
You may choose new targets for target spell or ability.

Morphic Pool

Morphic Pool enters tapped unless you have two or more opponents.
{T}: Add {U} or {B}.

Dockside Extortionist

When Dockside Extortionist enters, create X Treasure tokens, where X is the number of artifacts and enchantments your opponents control. (Treasure tokens are artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Exotic Orchard

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

Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is Esper Sentinel's power.

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Chrome Mox

Imprint — When Chrome Mox enters, you may exile a nonartifact, nonland card from your hand.
{T}: Add one mana of any of the exiled card's colors.

Wizard Class

(Gain the next level as a sorcery to add its ability.)
You have no maximum hand size.
{2}{U}: Level 2
When this Class becomes level 2, draw two cards.
{4}{U}: Level 3
Whenever you draw a card, put a +1/+1 counter on target creature you control.

Necropotence

Skip your draw step.
Whenever you discard a card, exile that card from your graveyard.
Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.

Polluted Delta

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

Shadowspear

Equipped creature gets +1/+1 and has trample and lifelink.
{1}: Permanents your opponents control lose hexproof and indestructible until end of turn.
Equip {2}

Thassa's Oracle

When Thassa's Oracle enters, look at the top X cards of your library, where X is your devotion to blue. Put up to one of them on top of your library and the rest on the bottom of your library in a random order. If X is greater than or equal to the number of cards in your library, you win the game. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Pithing Needle

As Pithing Needle enters, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

Sensei's Divining Top

{1}: Look at the top three cards of your library, then put them back in any order.
{T}: Draw a card, then put Sensei's Divining Top on top of its owner's library.

Mana Confluence

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

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Dispel

Consecrated Sphinx

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

Notion Thief

Flash
If an opponent would draw a card except the first one they draw in each of their draw steps, instead that player skips that draw and you draw a card.

Snow-Covered Island

Blood Crypt

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

Scrubland

Delay

Counter target spell. If the spell is countered this way, exile it with three time counters on it instead of putting it into its owner's graveyard. If it doesn't have suspend, it gains suspend. (At the beginning of its owner's upkeep, they remove a time counter. When the last is removed, they may play it without paying its mana cost. If it's a creature, it has haste.)

Tymna the Weaver

Lifelink
At the beginning of each of your postcombat main phases, you may pay X life, where X is the number of opponents that were dealt combat damage this turn. If you do, draw X cards.
Partner (You can have two commanders if both have partner.)

Hushbringer

Flying, lifelink
Creatures entering or dying don't cause abilities to trigger.

Silence

Your opponents can't cast spells this turn.

Damn

Destroy target creature. A creature destroyed this way can't be regenerated.
Overload {2}{W}{W} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Mox Opal

Metalcraft — {T}: Add one mana of any color. Activate only if you control three or more artifacts.

Lim-Dûl's Vault

Look at the top five cards of your library. As many times as you choose, you may pay 1 life, put those cards on the bottom of your library in any order, then look at the top five cards of your library. Then shuffle and put the last cards you looked at this way on top in any order.

Vault of Champions

Vault of Champions enters tapped unless you have two or more opponents.
{T}: Add {W} or {B}.

Chain of Vapor

Return target nonland permanent to its owner's hand. Then that permanent's controller may sacrifice a land of their choice. If the player does, they may copy this spell and may choose a new target for that copy.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Ancient Tomb

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

Izzet Staticaster

Flash (You may cast this spell any time you could cast an instant.)
Haste
{T}: Izzet Staticaster deals 1 damage to target creature and each other creature with the same name as that creature.

Toothy, Imaginary Friend

Partner with Pir, Imaginative Rascal (When this creature enters, target player may put Pir into their hand from their library, then shuffle.)
Whenever you draw a card, put a +1/+1 counter on Toothy, Imaginary Friend.
When Toothy leaves the battlefield, draw a card for each +1/+1 counter on it.

Tainted Pact

Exile the top card of your library. You may put that card into your hand unless it has the same name as another card exiled this way. Repeat this process until you put a card into your hand or you exile two cards with the same name, whichever comes first.

Kira, Great Glass-Spinner

Flying
Creatures you control have "Whenever this creature becomes the target of a spell or ability for the first time each turn, counter that spell or ability."

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Snow-Covered Swamp

Imperial Seal

Fire Covenant

As an additional cost to cast this spell, pay X life.
Fire Covenant deals X damage divided as you choose among any number of target creatures.

Serra Ascendant

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
As long as you have 30 or more life, Serra Ascendant gets +5/+5 and has flying.

Demonic Consultation

Choose a card name. Exile the top six cards of your library, then reveal cards from the top of your library until you reveal a card with the chosen name. Put that card into your hand and exile all other cards revealed this way.

Fracture

Destroy target artifact, enchantment, or planeswalker.

Inferno Titan

{R}: Inferno Titan gets +1/+0 until end of turn.
Whenever Inferno Titan enters or attacks, it deals 3 damage divided as you choose among one, two, or three targets.

Grim Hireling

Whenever one or more creatures you control deal combat damage to a player, create two Treasure tokens.
{B}, Sacrifice X Treasures: Target creature gets -X/-X until end of turn. Activate only as a sorcery.

Dovin's Veto

This spell can't be countered.
Counter target noncreature spell.

Forbidden Orchard

{T}: Add one mana of any color.
Whenever you tap Forbidden Orchard for mana, target opponent creates a 1/1 colorless Spirit creature token.

Rhystic Study

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

Grim Monolith

Grim Monolith doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{4}: Untap Grim Monolith.

Damping Matrix

Activated abilities of artifacts and creatures can't be activated unless they're mana abilities.

Force of Negation

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.
Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Aven Mindcensor

Flash
Flying
If an opponent would search a library, that player searches the top four cards of that library instead.

Alms Collector

Flash
If an opponent would draw two or more cards, instead you and that player each draw a card.

Samurai of the Pale Curtain

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)
If a permanent would be put into a graveyard, exile it instead.

Sudden Demise

Choose a color. Sudden Demise deals X damage to each creature of the chosen color.

Linvala, Keeper of Silence

Flying
Activated abilities of creatures your opponents control can't be activated.

Wooded Foothills

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

Red Elemental Blast

Choose one —
• Counter target blue spell.
• Destroy target blue permanent.

Meltdown

Destroy each artifact with mana value X or less.

Hallowed Fountain

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

Rest in Peace

When Rest in Peace enters, exile all graveyards.
If a card or token would be put into a graveyard from anywhere, exile it instead.

Solitude

Flash
Lifelink
When Solitude enters, exile up to one other target creature. That creature's controller gains life equal to its power.
Evoke—Exile a white card from your hand.

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Gemstone Caverns

If Gemstone Caverns is in your opening hand and you're not the starting player, you may begin the game with Gemstone Caverns on the battlefield with a luck counter on it. If you do, exile a card from your hand.
{T}: Add {C}. If Gemstone Caverns has a luck counter on it, instead add one mana of any color.

Snow-Covered Plains

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Command Tower

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

Weathered Runestone

Nonland permanent cards in graveyards and libraries can't enter the battlefield.
Players can't cast spells from graveyards or libraries.

Jeweled Lotus

{T}, Sacrifice Jeweled Lotus: Add three mana of any one color. Spend this mana only to cast your commander.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Urza's Saga gains "{T}: Add {C}."
II — Urza's Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This creature gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Sol Ring

Marsh Flats

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

Tundra

Talisman of Creativity

{T}: Add {C}.
{T}: Add {U} or {R}. Talisman of Creativity deals 1 damage to you.

Containment Priest

Flash
If a nontoken creature would enter and it wasn't cast, exile it instead.

Flusterstorm

Counter target instant or sorcery spell unless its controller pays {1}.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Phantasmal Image

You may have Phantasmal Image enter as a copy of any creature on the battlefield, except it's an Illusion in addition to its other types and it has "When this creature becomes the target of a spell or ability, sacrifice it."

Drannith Magistrate

Your opponents can't cast spells from anywhere other than their hands.

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}.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.