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.

Phyrexian Ingester

Imprint — When this creature enters, you may exile target nontoken creature.
This creature gets +X/+Y, where X is the exiled creature card's power and Y is its toughness.

Kaervek the Merciless

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

Inkshield

Prevent all combat damage that would be dealt to you this turn. For each 1 damage prevented this way, create a 2/1 white and black Inkling creature token with flying.

Theoretical Duplication

Whenever a nontoken creature an opponent controls enters this turn, create a token that's a copy of that creature.

Planeswalker's Favor

{3}{G}: Target opponent reveals a card at random from their hand. Target creature gets +X/+X until end of turn, where X is the revealed card's mana value.

Jaheira's Respite

Search your library for up to X basic land cards, where X is the number of creatures attacking you, put those cards onto the battlefield tapped, then shuffle.
Prevent all combat damage that would be dealt this turn.

Honorable Passage

The next time a source of your choice would deal damage to any target this turn, prevent that damage. If damage from a red source is prevented this way, Honorable Passage deals that much damage to the source's controller.

Tainted Remedy

If an opponent would gain life, that player loses that much life instead.

Deflecting Palm

The next time a source of your choice would deal damage to you this turn, prevent that damage. If damage is prevented this way, Deflecting Palm deals that much damage to that source's controller.

Bold Plagiarist

Flash
Whenever an opponent puts one or more counters on a creature they control, they put the same number and kind of counters on this creature.

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.

Seek

Search target opponent's library for a card and exile it. You gain life equal to its mana value. Then that player shuffles.

Hide

Put target artifact or enchantment on the bottom of its owner's library.

Hide // Seek

Consume

Target player sacrifices a creature with the greatest power among creatures they control. You gain life equal to its power.

Consecrate

Exile target card from a graveyard.
Draw a card.

Consecrate // Consume

Spell Swindle

Counter target spell. Create X Treasure tokens, where X is that spell's mana value. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Arachnogenesis

Create X 1/2 green Spider creature tokens with reach, where X is the number of creatures attacking you. Prevent all combat damage that would be dealt this turn by non-Spider creatures.

Invert Polarity

Choose target spell, then flip a coin. If you win the flip, gain control of that spell and you may choose new targets for it. If you lose the flip, counter that spell.

Noxious Gearhulk

Menace
When this creature enters, you may destroy another target creature. If a creature is destroyed this way, you gain life equal to its toughness.

Boros Fury-Shield

Prevent all combat damage that would be dealt by target attacking or blocking creature this turn. If {R} was spent to cast this spell, Boros Fury-Shield deals damage to that creature's controller equal to the creature's power.

Channel Harm

Prevent all damage that would be dealt to you and permanents you control this turn by sources you don't control. If damage is prevented this way, you may have Channel Harm deal that much damage to target creature.

Reflect Damage

The next time a source of your choice would deal damage this turn, that damage is dealt to that source's controller instead.

Deadly Tempest

Destroy all creatures. Each player loses life equal to the number of creatures they controlled that were destroyed this way.

Plagiarize

Until end of turn, if target player would draw a card, instead that player skips that draw and you draw a card.

Aura Mutation

Destroy target enchantment. Create X 1/1 green Saproling creature tokens, where X is that enchantment's mana value.

Twisted Justice

Target player sacrifices a creature of their choice. You draw cards equal to that creature's power.

Traitor's Roar

Tap target untapped creature. It deals damage equal to its power to its controller.
Conspire (As you cast this spell, you may tap two untapped creatures you control that share a color with it. When you do, copy it and you may choose a new target for the copy.)

Entrapment Maneuver

Target player sacrifices an attacking creature of their choice. You create X 1/1 white Soldier creature tokens, where X is that creature's toughness.

Galadhrim Ambush

Create X 1/1 green Elf Warrior creature tokens, where X is the number of attacking creatures.
Prevent all combat damage that would be dealt this turn by non-Elf creatures.

Wernog, Rider's Chaplain

When Wernog, Rider's Chaplain enters or leaves the battlefield, each opponent may investigate. Each opponent who doesn't loses 1 life. You investigate X times, where X is one plus the number of opponents who investigated this way.
Friends forever (You can have two commanders if both have friends forever.)

Bjorna, Nightfall Alchemist

{T}, Sacrifice an artifact: Bjorna, Nightfall Alchemist deals 1 damage to target creature. Goad that creature. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)
Friends forever (You can have two commanders if both have friends forever.)

Niv-Mizzet, Supreme

Flying, hexproof from monocolored
Each instant and sorcery card in your graveyard that's exactly two colors has jump-start. (You may cast that card from your graveyard by discarding a card in addition to paying its other costs. Then exile it.)

Crafty Cutpurse

Flash
When this creature enters, each token that would be created under an opponent's control this turn is created under your control instead.

Aether Mutation

Return target creature to its owner's hand. Create X 1/1 green Saproling creature tokens, where X is that creature's mana value.

Access Denied

Counter target spell. Create X 1/1 colorless Thopter artifact creature tokens with flying, where X is that spell's mana value.

Death Mutation

Destroy target nonblack creature. It can't be regenerated. Create X 1/1 green Saproling creature tokens, where X is that creature's mana value.

Runeflare Trap

If an opponent drew three or more cards this turn, you may pay {R} rather than pay this spell's mana cost.
Runeflare Trap deals damage to target player equal to the number of cards in that player's hand.

Essence Backlash

Counter target creature spell. Essence Backlash deals damage equal to that spell's power to its controller.

Omnath, Locus of All

If you would lose unspent mana, that mana becomes black instead.
At the beginning of your first main phase, look at the top card of your library. You may reveal that card if it has three or more colored mana symbols in its mana cost. If you do, add three mana in any combination of its colors and put it into your hand. If you don't reveal it, put it into your hand.

Alms Collector

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

Rakdos Charm

Choose one —
• Exile target player's graveyard.
• Destroy target artifact.
• Each creature deals 1 damage to its controller.

Plasm Capture

Counter target spell. At the beginning of your next first main phase, add X mana in any combination of colors, where X is that spell's mana value.

Aboleth Spawn

Flash
Ward {2}
Probing Telepathy — Whenever a creature entering under an opponent's control causes a triggered ability of that creature to trigger, you may copy that ability. You may choose new targets for the copy.

Enchanter's Bane

At the beginning of your end step, target enchantment deals damage equal to its mana value to its controller unless that player sacrifices it.

Ravenous Slime

This creature can't be blocked by creatures with power 2 or less.
If a creature an opponent controls would die, instead exile it and put a number of +1/+1 counters equal to that creature's power on this creature.

Artifact Mutation

Destroy target artifact. It can't be regenerated. Create X 1/1 green Saproling creature tokens, where X is that artifact's mana value.

Reinterpret

Counter target spell. You may cast a spell with equal or lesser mana value from your hand without paying its mana cost.

Selfless Squire

Flash
When this creature enters, 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 this creature.

Delirium

Cast this spell only during an opponent's turn.
Tap target creature that player controls. That creature deals damage equal to its power to the player. Prevent all combat damage that would be dealt to and dealt by the creature this turn.

Smirking Spelljacker

Flash
Flying
When this creature enters, exile target spell an opponent controls.
Whenever this creature attacks, if a card is exiled with it, you may cast the exiled card without paying its mana cost.

Mystic Genesis

Counter target spell. Create an X/X green Ooze creature token, where X is that spell's mana value.

Gather Specimens

If a creature would enter the battlefield under an opponent's control this turn, it enters under your control instead.

Olórin's Searing Light

Each opponent exiles a creature with the greatest power among creatures that player controls.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, Olórin's Searing Light deals damage to each opponent equal to the power of the creature they exiled.

Comeuppance

Prevent all damage that would be dealt to you and planeswalkers you control this turn by sources you don't control. If damage from a creature source is prevented this way, Comeuppance deals that much damage to that creature. If damage from a noncreature source is prevented this way, Comeuppance deals that much damage to the source's controller.

Cooperate

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Copy target instant or sorcery spell. You may choose new targets for the copy.

Refuse

Refuse deals damage to target spell's controller equal to that spell's mana value.