Bitter Feud

As Bitter Feud enters, choose two players.
If a source controlled by one of the chosen players would deal damage to the other chosen player or a permanent that player controls, that source deals double that damage to that player or permanent instead.

Archangel of Strife

Flying
As Archangel of Strife enters, each player chooses war or peace.
Creatures controlled by players who chose war get +3/+0.
Creatures controlled by players who chose peace get +0/+3.

Radiate

Choose target instant or sorcery spell that targets only a single permanent or player. Copy that spell for each other permanent or player the spell could target. Each copy targets a different one of those permanents and players.

Soul Conduit

{6}, {T}: Two target players exchange life totals.

Single Combat

Each player chooses a creature or planeswalker they control, then sacrifices the rest. Players can't cast creature or planeswalker spells until the end of your next turn.

Price of Knowledge

Players have no maximum hand size.
At the beginning of each opponent's upkeep, Price of Knowledge deals damage to that player equal to the number of cards in that player's hand.

Scourge of the Skyclaves

Kicker {4}{B}
When you cast this spell, if it was kicked, each player loses half their life, rounded up.
Scourge of the Skyclaves's power and toughness are each equal to 20 minus the highest life total among players.

Surveyor's Scope

{T}, Exile Surveyor's Scope: Search your library for up to X basic land cards, where X is the number of players who control at least two more lands than you. Put those cards onto the battlefield, then shuffle.

Skull Rend

Skull Rend deals 2 damage to each opponent. Those players each discard two cards at random.

Run Away Together

Choose two target creatures controlled by different players. Return those creatures to their owners' hands.

Loxodon Peacekeeper

At the beginning of your upkeep, the player with the lowest life total gains control of Loxodon Peacekeeper. If two or more players are tied for lowest life total, you choose one of them, and that player gains control of Loxodon Peacekeeper.

Kaboom!

Choose any number of target players or planeswalkers. For each of them, reveal cards from the top of your library until you reveal a nonland card, Kaboom! deals damage equal to that card's mana value to that player or planeswalker, then you put the revealed cards on the bottom of your library in any order.

Hive Mind

Whenever a player casts an instant or sorcery spell, each other player copies that spell. Each of those players may choose new targets for their copy.

Sower of Discord

Flying
As Sower of Discord enters, choose two players.
Whenever damage is dealt to one of the chosen players, the other chosen player also loses that much life.

Repay in Kind

Each player's life total becomes the lowest life total among all players.

Jace, Memory Adept

+1: Draw a card. Target player mills a card.
0: Target player mills ten cards.
−7: Any number of target players each draw twenty cards.

Axis of Mortality

At the beginning of your upkeep, you may have two target players exchange life totals.

Soulfire Eruption

Choose any number of target creatures, planeswalkers, and/or players. For each of them, exile the top card of your library, then Soulfire Eruption deals damage equal to that card's mana value to that permanent or player. You may play the exiled cards until the end of your next turn.

Aurelia's Fury

Aurelia's Fury deals X damage divided as you choose among any number of targets. Tap each creature dealt damage this way. Players dealt damage this way can't cast noncreature spells this turn.

Restore Balance

Suspend 6—{W}
Each player chooses a number of lands they control equal to the number of lands controlled by the player who controls the fewest, then sacrifices the rest. Players sacrifice creatures and discard cards the same way.

Winds of Abandon

Exile target creature you don't control. For each creature exiled this way, its controller searches their library for a basic land card. Those players put those cards onto the battlefield tapped, then shuffle.
Overload {4}{W}{W} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Camouflage

Cast this spell only during your declare attackers step.
This turn, instead of declaring blockers, each defending player chooses any number of creatures they control and divides them into a number of piles equal to the number of attacking creatures for whom that player is the defending player. Creatures those players control that can block additional creatures may likewise be put into additional piles. Assign each pile to a different one of those attacking creatures at random. Each creature in a pile that can block the creature that pile is assigned to does so. (Piles can be empty.)

Witch Hunt

Players can't gain life.
At the beginning of your upkeep, Witch Hunt deals 4 damage to you.
At the beginning of your end step, target opponent chosen at random gains control of Witch Hunt.

Defend the Hearth

Prevent all combat damage that would be dealt to players this turn.

Havoc Festival

Players can't gain life.
At the beginning of each player's upkeep, that player loses half their life, rounded up.

Radiant Performer

Flash
When Radiant Performer enters, if you cast it from your hand, choose target spell or ability that targets only a single permanent or player. Copy that spell or ability for each other permanent or player the spell or ability could target. Each copy targets a different one of those permanents and players.

Court of Cunning

When Court of Cunning enters, you become the monarch.
At the beginning of your upkeep, any number of target players each mill two cards. If you're the monarch, each of those players mills ten cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

Cornered Market

Players can't cast spells with the same name as a nontoken permanent.
Players can't play nonbasic lands with the same name as a nontoken permanent.

Magus of the Balance

{4}{W}, {T}, Sacrifice Magus of the Balance: Each player chooses a number of lands they control equal to the number of lands controlled by the player who controls the fewest, then sacrifices the rest. Players discard cards and sacrifice creatures the same way.

Profane Transfusion

Two target players exchange life totals. You create an X/X colorless Horror artifact creature token, where X is the difference between those players' life totals.

Reverse the Sands

Redistribute any number of players' life totals. (Each of those players gets one life total back.)

Scheming Symmetry

Choose two target players. Each of them searches their library for a card, then shuffles and puts that card on top.

Mana Maze

Players can't cast spells that share a color with the spell most recently cast this turn.

Tainted Sigil

{T}, Sacrifice Tainted Sigil: You gain life equal to the total life lost by all players this turn. (Damage causes loss of life.)

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.

Folio of Fancies

Players have no maximum hand size.
{X}{X}, {T}: Each player draws X cards.
{2}{U}, {T}: Each opponent mills cards equal to the number of cards in their hand.

Field of Dreams

Players play with the top card of their libraries revealed.

Chameleon Blur

Prevent all damage that creatures would deal to players this turn.

Peace Talks

This turn and next turn, creatures can't attack, and players and permanents can't be the targets of spells or activated abilities.

Grudge Keeper

Whenever players finish voting, each opponent who voted for a choice you didn't vote for loses 2 life.

The Immortal Sun

Players can't activate planeswalkers' loyalty abilities.
At the beginning of your draw step, draw an additional card.
Spells you cast cost {1} less to cast.
Creatures you control get +1/+1.

Shower of Coals

Shower of Coals deals 2 damage to each of up to three targets.
Threshold — Shower of Coals deals 4 damage to each of those permanents and/or players instead if seven or more cards are in your graveyard.

Hunters' Feast

Any number of target players each gain 6 life.

Weathered Sentinels

Defender, vigilance, reach, trample
Weathered Sentinels can attack players who attacked you during their last turn as though it didn't have defender.
Whenever Weathered Sentinels attacks, it gets +3/+3 and gains indestructible until end of turn.

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.

Commencement of Festivities

Arbiter of Knollridge

Vigilance
When Arbiter of Knollridge enters, each player's life total becomes the highest life total among all players.

Reward the Faithful

Any number of target players each gain life equal to the highest mana value among permanents you control.

Curse of Surveillance

Enchant player
At the beginning of enchanted player's upkeep, any number of target players other than that player each draw cards equal to the number of Curses attached to that player.

Chaos Mutation

Exile any number of target creatures controlled by different players. For each creature exiled this way, its controller reveals cards from the top of their library until they reveal a creature card, puts that card onto the battlefield, then puts the rest on the bottom of their library in a random order.

Cultural Exchange

Choose any number of creatures target player controls. Choose the same number of creatures another target player controls. Those players exchange control of those creatures. (This effect lasts indefinitely.)

Skullcrack

Players can't gain life this turn. Damage can't be prevented this turn. Skullcrack deals 3 damage to target player or planeswalker.

Omen Machine

Players can't draw cards.
At the beginning of each player's draw step, that player exiles the top card of their library. If it's a land card, the player puts it onto the battlefield. Otherwise, the player casts it without paying its mana cost if able.

Ashes of the Abhorrent

Players can't cast spells from graveyards or activate abilities of cards in graveyards.
Whenever a creature dies, you gain 1 life.

Modify Memory

Exchange control of two target creatures controlled by different players. If you control neither creature, draw three cards.

Huddle Up

Assist (Another player can pay up to {2} of this spell's cost.)
Two target players each draw a card.

Oreskos Explorer

When Oreskos Explorer enters, search your library for up to X Plains cards, where X is the number of players who control more lands than you. Reveal those cards, put them into your hand, then shuffle.