Arbiter of Knollridge

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

Scandalmonger

{2}: Target player discards a card. Any player may activate this ability but only as a sorcery.

Kynaios and Tiro of Meletis

At the beginning of your end step, draw a card. Each player may put a land card from their hand onto the battlefield, then each opponent who didn't draws a card.

Breena, the Demagogue

Flying
Whenever a player attacks one of your opponents, if that opponent has more life than another of your opponents, that attacking player draws a card and you put two +1/+1 counters on a creature you control.

Eye of Doom

When Eye of Doom enters, each player chooses a nonland permanent and puts a doom counter on it.
{2}, {T}, Sacrifice Eye of Doom: Destroy each permanent with a doom counter on it.

Phelddagrif

{G}: Phelddagrif gains trample until end of turn. Target opponent creates a 1/1 green Hippo creature token.
{W}: Phelddagrif gains flying until end of turn. Target opponent gains 2 life.
{U}: Return Phelddagrif to its owner's hand. Target opponent may draw a card.

Font of Mythos

At the beginning of each player's draw step, that player draws two additional cards.

Seedtime

Cast this spell only during your turn.
Take an extra turn after this one if an opponent cast a blue spell this turn.

Sailmonger

{2}: Target creature gains flying until end of turn. Any player may activate this ability.

Black Market

Whenever a creature dies, put a charge counter on Black Market.
At the beginning of your first main phase, add {B} for each charge counter on Black Market.

Pendant of Prosperity

Pendant of Prosperity enters under the control of an opponent of your choice.
{2}, {T}: Draw a card, then you may put a land card from your hand onto the battlefield. Pendant of Prosperity's owner draws a card, then that player may put a land card from their hand onto the battlefield.

Mana Cache

At the beginning of each player's end step, put a charge counter on Mana Cache for each untapped land that player controls.
Remove a charge counter from Mana Cache: Add {C}. Any player may activate this ability but only during their turn before the end step.

Withering Boon

As an additional cost to cast this spell, pay 3 life.
Counter target creature spell.

Spreading Plague

Whenever a creature enters, destroy all other creatures that share a color with it. They can't be regenerated.

Reins of Power

Untap all creatures you control and all creatures target opponent controls. You and that opponent each gain control of all creatures the other controls until end of turn. Those creatures gain haste until end of turn.

Spellweaver Volute

Enchant instant card in a graveyard
Whenever you cast a sorcery spell, copy the enchanted instant card. You may cast the copy without paying its mana cost. If you do, exile the enchanted card and attach Spellweaver Volute to another instant card in a graveyard.

Braids, Conjurer Adept

At the beginning of each player's upkeep, that player may put an artifact, creature, or land card from their hand onto the battlefield.

Heartbeat of Spring

Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

Dimensional Breach

Exile all permanents. For as long as any of those cards remain exiled, at the beginning of each player's upkeep, that player returns one of the exiled cards they own to the battlefield.

Well of Knowledge

{2}: Draw a card. Any player may activate this ability but only during their draw step.

Helix Pinnacle

Shroud (This enchantment can't be the target of spells or abilities.)
{X}: Put X tower counters on Helix Pinnacle.
At the beginning of your upkeep, if there are 100 or more tower counters on Helix Pinnacle, you win the game.

Death Cloud

Each player loses X life, discards X cards, sacrifices X creatures of their choice, then sacrifices X lands of their choice.

Pain's Reward

Each player may bid life. You start the bidding with a bid of any number. 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 draws four cards.

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.

Warmonger

{2}: Warmonger deals 1 damage to each creature without flying and each player. Any player may activate this ability.

Squallmonger

{2}: Squallmonger deals 1 damage to each creature with flying and each player. Any player may activate this ability.

Polymorphist's Jest

Until end of turn, each creature target player controls loses all abilities and becomes a blue Frog with base power and toughness 1/1.

Questing Phelddagrif

{G}: Questing Phelddagrif gets +1/+1 until end of turn. Target opponent creates a 1/1 green Hippo creature token.
{W}: Questing Phelddagrif gains protection from black and from red until end of turn. Target opponent gains 2 life.
{U}: Questing Phelddagrif gains flying until end of turn. Target opponent may draw a card.

Mirror Strike

All combat damage that would be dealt to you this turn by target unblocked creature is dealt to its controller instead.

Fortunate Few

Choose a nonland permanent you don't control, then each other player chooses a nonland permanent they don't control that hasn't been chosen this way. Destroy all other nonland permanents.

Fractured Identity

Exile target nonland permanent. Each player other than its controller creates a token that's a copy of it.

Head Games

Target opponent puts the cards from their hand on top of their library. Search that player's library for that many cards. The player puts those cards into their hand, then shuffles.

Wishmonger

{2}: Target creature gains protection from the color of its controller's choice until end of turn. Any player may activate this ability.

Phage the Untouchable

When Phage the Untouchable enters, if you didn't cast it from your hand, you lose the game.
Whenever Phage deals combat damage to a creature, destroy that creature. It can't be regenerated.
Whenever Phage deals combat damage to a player, that player loses the game.

Oath of Lieges

At the beginning of each player's upkeep, that player chooses target player who controls more lands than they do and is their opponent. The first player may search their library for a basic land card, put that card onto the battlefield, then shuffle.

Mindmoil

Whenever you cast a spell, put the cards in your hand on the bottom of your library in any order, then draw that many cards.

Jace's Archivist

{U}, {T}: Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Repay in Kind

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

Temporal Extortion

When you cast this spell, any player may pay half their life, rounded up. If a player does, counter Temporal Extortion.
Take an extra turn after this one.

Kenrith, the Returned King

{R}: All creatures gain trample and haste until end of turn.
{1}{G}: Put a +1/+1 counter on target creature.
{2}{W}: Target player gains 5 life.
{3}{U}: Target player draws a card.
{4}{B}: Put target creature card from a graveyard onto the battlefield under its owner's control.