Aethersnatch

Gain control of target spell. You may choose new targets for it. (If that spell becomes a permanent, it enters under your control.)

Alexios, Deimos of Kosmos

Trample
Alexios, Deimos of Kosmos attacks each combat if able, can't be sacrificed, and can't attack its owner.
At the beginning of each player's upkeep, that player gains control of Alexios, untaps it, and puts a +1/+1 counter on it. It gains haste until end of turn.

Curse of Echoes

Enchant player
Whenever enchanted player casts an instant or sorcery spell, each other player may copy that spell and may choose new targets for the copy they control.

Goblin Game

Each player hides at least one item, then all players reveal them simultaneously. Each player loses life equal to the number of items they revealed. The player who revealed the fewest items then loses half their life, rounded up. If two or more players are tied for fewest, each loses half their life, rounded up.

Clinging Mists

Prevent all combat damage that would be dealt this turn.
Fateful hour — If you have 5 or less life, tap all attacking creatures. Those creatures don't untap during their controller's next untap step.

Misfortune

An opponent chooses one —
• You put a +1/+1 counter on each creature you control and gain 4 life.
• You put a -1/-1 counter on each creature that player controls and Misfortune deals 4 damage to that player.

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.

Rebound

Change the target of target spell that targets only a player. The new target must be a player.

Vault 11: Voter's Dilemma

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — For each opponent, you create a 1/1 white Human Soldier creature token.
II, III — Each player secretly votes for up to one creature, then those votes are revealed. If no creature got votes, each player draws a card. Otherwise, destroy each creature with the most votes or tied for most votes.

Reverse Damage

The next time a source of your choice would deal damage to you this turn, prevent that damage. You gain life equal to the damage prevented this way.

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.

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.

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.

Split Decision

Will of the council — Choose target instant or sorcery spell. Starting with you, each player votes for denial or duplication. If denial gets more votes, counter the spell. If duplication gets more votes or the vote is tied, copy the spell. You may choose new targets for the copy.

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.

Wedding Ring

When Wedding Ring enters, if it was cast, target opponent creates a token that's a copy of it.
Whenever an opponent who controls an artifact named Wedding Ring draws a card during their turn, you draw a card.
Whenever an opponent who controls an artifact named Wedding Ring gains life during their turn, you gain that much life.

Prisoner's Dilemma

Each opponent secretly chooses silence or snitch, then the choices are revealed. If each opponent chose silence, Prisoner's Dilemma deals 4 damage to each of them. If each opponent chose snitch, Prisoner's Dilemma deals 8 damage to each of them. Otherwise, Prisoner's Dilemma deals 12 damage to each opponent who chose silence.
Flashback {5}{R}{R}

Sudden Substitution

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Exchange control of target noncreature spell and target creature. Then the spell's controller may choose new targets for it.

Mirror Sheen

{1}{U/R}{U/R}: Copy target instant or sorcery spell that targets you. You may choose new targets for the copy.

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.

Brash Taunter

Indestructible
Whenever Brash Taunter is dealt damage, it deals that much damage to target opponent.
{2}{R}, {T}: Brash Taunter fights another target creature.

Game of Chaos

Flip a coin. If you win the flip, you gain 1 life and target opponent loses 1 life, and you decide whether to flip again. If you lose the flip, you lose 1 life and that opponent gains 1 life, and that player decides whether to flip again. Double the life stakes with each flip.

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.

Tempt with Mayhem

Tempting offer — Choose target instant or sorcery spell. Each opponent may copy that spell and may choose new targets for the copy they control. You copy that spell once plus an additional time for each opponent who copied the spell this way. You may choose new targets for the copies you control.

Phytohydra

If damage would be dealt to Phytohydra, put that many +1/+1 counters on it instead.

Angelsong

Prevent all combat damage that would be dealt this turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

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.

Return the Favor

Spree (Choose one or more additional costs.)
+ {1} — Copy target instant spell, sorcery spell, activated ability, or triggered ability. You may choose new targets for the copy.
+ {1} — Change the target of target spell or ability with a single target.

Blunt the Assault

You gain 1 life for each creature on the battlefield. Prevent all combat damage that would be dealt this turn.

Petrahydrox

({U/R} can be paid with either {U} or {R}.)
When Petrahydrox becomes the target of a spell or ability, return Petrahydrox to its owner's hand.

Illicit Auction

Each player may bid life for control of target creature. You start the bidding with a bid of 0. In turn order, each player may top the high bid. The bidding ends if the high bid stands. The high bidder loses life equal to the high bid and gains control of the creature. (This effect lasts indefinitely.)

Misleading Signpost

Flash
When Misleading Signpost enters during the declare attackers step, you may reselect which player or permanent target attacking creature is attacking. (It can't attack its controller or their permanents.)
{T}: Add {U}.

Stuffy Doll

Indestructible
As Stuffy Doll enters, choose a player.
Whenever Stuffy Doll is dealt damage, it deals that much damage to the chosen player.
{T}: Stuffy Doll deals 1 damage to itself.

Inquisitor's Snare

Prevent all damage target attacking or blocking creature would deal this turn. If that creature is black or red, destroy it.

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.

Awe Strike

The next time target creature would deal damage this turn, prevent that damage. You gain life equal to the damage prevented this way.

Wyll's Reversal

Choose target spell or ability with one or more targets. Roll a d20 and add the greatest power among creatures you control.
1—14 | You may choose new targets for that spell or ability.
15+ | You may choose new targets for that spell or ability. Then copy it. You may choose new targets for the copy.

Sadistic Shell Game

Starting with the next opponent in turn order, each player chooses a creature you don't control. Destroy the chosen creatures.

Dazzling Reflection

You gain life equal to target creature's power. The next time that creature would deal damage this turn, prevent that damage.

Hallow

Prevent all damage target spell would deal this turn. You gain life equal to the damage prevented this way.

Gauntlets of Chaos

{5}, Sacrifice Gauntlets of Chaos: Exchange control of target artifact, creature, or land you control and target permanent an opponent controls that shares one of those types with it. If those permanents are exchanged this way, destroy all Auras attached to them.

Gale's Redirection

Exile target spell, then roll a d20 and add that spell's mana value.
1—14 | You may cast the exiled card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast that spell.
15+ | You may cast the exiled card without paying its mana cost for as long as it remains exiled.

Batwing Brume

Prevent all combat damage that would be dealt this turn if {W} was spent to cast this spell. Each player loses 1 life for each attacking creature they control if {B} was spent to cast this spell. (Do both if {W}{B} was spent.)

You Look Upon the Tarrasque

Choose one —
• Run and Hide — Prevent all combat damage that would be dealt to you and creatures you control this turn.
• Gather Your Courage — Target creature gets +5/+5 and gains indestructible until end of turn. All creatures your opponents control able to block that creature this turn do so.

Wrong Turn

Target opponent gains control of target creature. (If an attacking or blocking creature changes controllers, it's removed from combat.)

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.

Chant of Vitu-Ghazi

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Prevent all damage that would be dealt by creatures this turn. You gain life equal to the damage prevented this way.

Mists of Lórien

Replicate {U} (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copies.)
Return target nonland permanent and each other nonland permanent with the same mana value as that permanent to their owners' hands.

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.

Refuse // Cooperate

Meletis Charlatan

{2}{U}, {T}: The controller of target instant or sorcery spell copies it. That player may choose new targets for the copy.

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.

Redirect

You may choose new targets for target spell.

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.

Rhystic Study

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

Wheel of Misfortune

Each player secretly chooses a number 0 or greater, then all players reveal those numbers simultaneously and determine the highest and lowest numbers revealed this way. Wheel of Misfortune deals damage equal to the highest number to each player who chose that number. Each player who didn't choose the lowest number discards their hand, then draws seven cards.

The Millennium Calendar

Whenever you untap one or more permanents during your untap step, put that many time counters on The Millennium Calendar.
{2}, {T}: Double the number of time counters on The Millennium Calendar.
When there are 1,000 or more time counters on The Millennium Calendar, sacrifice it and each opponent loses 1,000 life.

Perplexing Chimera

Whenever an opponent casts a spell, you may exchange control of Perplexing Chimera and that spell. If you do, you may choose new targets for the spell. (If the spell becomes a permanent, you control that permanent.)

Blessed Respite

Target player shuffles their graveyard into their library. Prevent all combat damage that would be dealt this turn.

Emissary of Grudges

Flying, haste
As Emissary of Grudges enters, secretly choose an opponent.
Reveal the player you chose: Choose new targets for target spell or ability if it's controlled by the chosen player and if it targets you or a permanent you control. Activate only once.

Time Wipe

Return a creature you control to its owner's hand, then destroy all creatures.

Wild Ricochet

You may choose new targets for target instant or sorcery spell. Then copy that spell. You may choose new targets for the copy.

Role Reversal

Exchange control of two target permanents that share a permanent type.

Psychic Rebuttal

Counter target instant or sorcery spell that targets you.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, you may copy the spell countered this way. You may choose new targets for the copy.

Divine Deflection

Prevent the next X damage that would be dealt to you and/or permanents you control this turn. If damage is prevented this way, Divine Deflection deals that much damage to any target.

Narset's Reversal

Copy target instant or sorcery spell, then return it to its owner's hand. You may choose new targets for the copy.

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 artifact: Add one mana of any color.")

Plargg and Nassari

At the beginning of your upkeep, each player exiles cards from the top of their library until they exile a nonland card. An opponent chooses a nonland card exiled this way. You may cast up to two spells from among the other cards exiled this way without paying their mana costs.

Glasses of Urza

Riot Control

You gain 1 life for each creature your opponents control. Prevent all damage that would be dealt to you this turn.

Respite

Prevent all combat damage that would be dealt this turn. You gain 1 life for each attacking creature.

Chef's Kiss

Gain control of target spell that targets only a single permanent or player. Copy it, then reselect the targets at random for the spell and the copy. The new targets can't be you or a permanent you control.

Repercussion

Whenever a creature is dealt damage, Repercussion deals that much damage to that creature's controller.

Darkness

Prevent all combat damage that would be dealt this turn.

Thieves' Auction

Exile all nontoken permanents. Starting with you, each player chooses one of the exiled cards and puts it onto the battlefield tapped under their control. Repeat this process until all cards exiled this way have been chosen.

Fealty to the Realm

Enchant creature
When Fealty to the Realm enters, you become the monarch.
The monarch controls enchanted creature.
Enchanted creature attacks each combat if able and can't attack you.

Ian Malcolm, Chaotician

Whenever a player draws their second card each turn, that player exiles the top card of their library.
During each player's turn, that player may cast a spell from among the cards they don't own exiled with Ian Malcolm, Chaotician, and mana of any type can be spent to cast it.

Dawn Charm

Choose one —
• Prevent all combat damage that would be dealt this turn.
• Regenerate target creature.
• Counter target spell that targets you.