Trail of the Mage-Rings

Instant and sorcery spells have rebound. (The spell's controller exiles the spell as it resolves if they cast it from their hand. At the beginning of that player's next upkeep, they may cast that card from exile without paying its mana cost.)
Whenever chaos ensues, you may search your library for an instant or sorcery card, reveal it, put it into your hand, then shuffle.

Astral Arena

No more than one creature can attack each combat.
No more than one creature can block each combat.
Whenever chaos ensues, Astral Arena deals 2 damage to each creature.

Mirrored Depths

Whenever a player casts a spell, that player flips a coin. If the player loses the flip, counter that spell.
Whenever chaos ensues, target player reveals the top card of their library. If it's a nonland card, you may cast it without paying its mana cost.

Kharasha Foothills

Whenever a creature you control attacks a player, for each other opponent, you may create a token that's a copy of that creature, tapped and attacking that opponent. Exile those tokens at the beginning of the next end step.
Whenever chaos ensues, you may sacrifice any number of creatures. If you do, Kharasha Foothills deals that much damage to target creature.

Takenuma

Whenever a creature leaves the battlefield, its controller draws a card.
Whenever chaos ensues, return target creature you control to its owner's hand.

Otaria

Instant and sorcery cards in graveyards have flashback. The flashback cost is equal to the card's mana cost. (Its owner may cast the card from their graveyard for its mana cost. Then they exile it.)
Whenever chaos ensues, take an extra turn after this one.

Hedron Fields of Agadeem

Creatures with power 7 or greater can't attack or block.
Whenever chaos ensues, create a 7/7 colorless Eldrazi creature token with annihilator 1. (Whenever it attacks, defending player sacrifices a permanent of their choice.)

Fields of Summer

Whenever a player casts a spell, that player may gain 2 life.
Whenever chaos ensues, you may gain 10 life.

Llanowar

All creatures have "{T}: Add {G}{G}."
Whenever chaos ensues, untap all creatures you control.

Glen Elendra

At end of combat, you may exchange control of target creature you control that dealt combat damage to a player this combat and target creature that player controls.
Whenever chaos ensues, gain control of target creature you own.

Izzet Steam Maze

Whenever a player casts an instant or sorcery spell, that player copies it. The player may choose new targets for the copy.
Whenever chaos ensues, instant and sorcery spells you cast this turn cost {3} less to cast.

Lair of the Ashen Idol

At the beginning of your upkeep, sacrifice a creature. If you can't, planeswalk.
Whenever chaos ensues, any number of target players each create a 2/2 black Zombie creature token.

Selesnya Loft Gardens

If an effect would create one or more tokens, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent, it puts twice that many of those counters on that permanent instead.
Whenever chaos ensues, until end of turn, whenever you tap a land for mana, add one mana of any type that land produced.

Grove of the Dreampods

When you planeswalk to Grove of the Dreampods and at the beginning of your upkeep, reveal cards from the top of your library until you reveal a creature card. Put that card onto the battlefield and the rest on the bottom of your library in a random order.
Whenever chaos ensues, return target creature card from your graveyard to the battlefield.

Immersturm

Whenever a creature enters, that creature's controller may have it deal damage equal to its power to any target of their choice.
Whenever chaos ensues, exile target creature, then return it to the battlefield under its owner's control.

The Eon Fog

Players skip their untap steps.
Whenever chaos ensues, untap all permanents you control.

Bant

All creatures have exalted. (Whenever a creature attacks alone, it gets +1/+1 until end of turn for each instance of exalted among permanents its controller controls.)
Whenever chaos ensues, put a divinity counter on target green, white, or blue creature. That creature has indestructible for as long as it has a divinity counter on it.

Stensia

Whenever a creature deals damage to one or more players for the first time each turn, put a +1/+1 counter on it.
Whenever chaos ensues, each creature you control gains "{T}: This creature deals 1 damage to target player or planeswalker" until end of turn.

Eloren Wilds

Whenever a player taps a permanent for mana, that player adds one mana of any type that permanent produced.
Whenever chaos ensues, target player can't cast spells until a player planeswalks.

Sanctum of Serra

When you planeswalk away from Sanctum of Serra, destroy all nonland permanents.
Whenever chaos ensues, you may have your life total become 20.

Orochi Colony

Whenever a creature you control deals combat damage to a player, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Whenever chaos ensues, target creature can't be blocked this turn.

Raven's Run

All creatures have wither. (They deal damage to creatures in the form of -1/-1 counters.)
Whenever chaos ensues, put a -1/-1 counter on target creature, two -1/-1 counters on another target creature, and three -1/-1 counters on a third target creature.

Furnace Layer

When you planeswalk to Furnace Layer and at the beginning of your upkeep, select target player at random. That player discards a card. If that player discards a land card this way, they lose 3 life.
Whenever chaos ensues, you may destroy target nonland permanent.

The Dark Barony

Whenever a nonblack card is put into a player's graveyard from anywhere, that player loses 1 life.
Whenever chaos ensues, each opponent discards a card.

Prahv

If you cast a spell this turn, you can't attack with creatures.
If you attacked with creatures this turn, you can't cast spells.
Whenever chaos ensues, you gain life equal to the number of cards in your hand.

Agyrem

Whenever a white creature dies, return it to the battlefield under its owner's control at the beginning of the next end step.
Whenever a nonwhite creature dies, return it to its owner's hand at the beginning of the next end step.
Whenever chaos ensues, creatures can't attack you until a player planeswalks.

Jund

Whenever a player casts a creature spell that's black, red, or green, it gains devour 5. (As that creature enters, you may sacrifice any number of creatures. It enters with five times that many +1/+1 counters on it.)
Whenever chaos ensues, create two 1/1 red Goblin creature tokens.

Kilnspire District

When you planeswalk to Kilnspire District and at the beginning of your first main phase, put a charge counter on Kilnspire District, then add {R} for each charge counter on it.
Whenever chaos ensues, you may pay {X}. If you do, Kilnspire District deals X damage to any target.

Horizon Boughs

All permanents untap during each player's untap step.
Whenever chaos ensues, you may search your library for up to three basic land cards, put them onto the battlefield tapped, then shuffle.

Edge of Malacol

If a creature you control would untap during your untap step, put two +1/+1 counters on it instead.
Whenever chaos ensues, untap each creature you control.

Murasa

Whenever a nontoken creature enters, its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.
Whenever chaos ensues, target land becomes a 4/4 creature that's still a land.

Spatial Merging

When you encounter Spatial Merging, reveal cards from the top of your planar deck until you reveal two plane cards. Simultaneously planeswalk to both of them. Put all other cards revealed this way on the bottom of your planar deck in any order.

The Aether Flues

When you planeswalk to The Aether Flues and at the beginning of your upkeep, you may sacrifice a creature. If you do, reveal cards from the top of your library until you reveal a creature card, put that card onto the battlefield, then shuffle all other cards revealed this way into your library.
Whenever chaos ensues, you may put a creature card from your hand onto the battlefield.

Towashi

Modified creatures you control have trample and "Whenever this creature deals combat damage to a player or planeswalker, draw a card." (Equipment, Auras you control, and counters are modifications.)
Whenever chaos ensues, distribute three +1/+1 counters among one, two, or three target creatures you control.

Talon Gates

Any time you could cast a sorcery, you may exile a nonland card from your hand with X time counters on it, where X is its mana value. If the exiled card 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, the player may cast it without paying its mana cost. If it's a creature, it has haste.)
Whenever chaos ensues, remove two time counters from each suspended card you own.

The Maelstrom

When you planeswalk to The Maelstrom and at the beginning of your upkeep, you may reveal the top card of your library. If it's a permanent card, you may put it onto the battlefield. If you revealed a card but didn't put it onto the battlefield, put it on the bottom of your library.
Whenever chaos ensues, return target permanent card from your graveyard to the battlefield.

Turri Island

Creature spells cost {2} less to cast.
Whenever chaos ensues, reveal the top three cards of your library. Put all creature cards revealed this way into your hand and the rest into your graveyard.

Akoum

Players may cast enchantment spells as though they had flash.
Whenever chaos ensues, destroy target creature that isn't enchanted.

Undercity Reaches

Whenever a creature deals combat damage to a player, its controller may draw a card.
Whenever chaos ensues, you have no maximum hand size for the rest of the game.

The Zephyr Maze

Creatures with flying get +2/+0.
Creatures without flying get -2/-0.
Whenever chaos ensues, target creature gains flying until end of turn.

Nephalia

At the beginning of your end step, mill seven cards. Then return a card at random from your graveyard to your hand.
Whenever chaos ensues, return target card from your graveyard to your hand.

Gavony

All creatures have vigilance.
Whenever chaos ensues, creatures you control gain indestructible until end of turn.

Quicksilver Sea

When you planeswalk to Quicksilver Sea and at the beginning of your upkeep, scry 4. (Look at the top four cards of your library, then put any number of them on the bottom and the rest on top in any order.)
Whenever chaos ensues, reveal the top card of your library. You may play it without paying its mana cost.

Lethe Lake

At the beginning of your upkeep, mill ten cards.
Whenever chaos ensues, target player mills ten cards.

Krosa

All creatures get +2/+2.
Whenever chaos ensues, you may add {W}{U}{B}{R}{G}.

Academy at Tolaria West

At the beginning of your end step, if you have no cards in hand, draw seven cards.
Whenever chaos ensues, discard your hand.

Naar Isle

At the beginning of your upkeep, put a flame counter on Naar Isle, then Naar Isle deals damage to you equal to the number of flame counters on it.
Whenever chaos ensues, Naar Isle deals 3 damage to target player or planeswalker.

Shiv

All creatures have "{R}: This creature gets +1/+0 until end of turn."
Whenever chaos ensues, create a 5/5 red Dragon creature token with flying.

Norn's Dominion

When you planeswalk away from Norn's Dominion, destroy each nonland permanent without a fate counter on it, then remove all fate counters from all permanents.
Whenever chaos ensues, you may put a fate counter on target permanent.

Morphic Tide

When you encounter Morphic Tide, each player shuffles all permanents they own into their library, then reveals that many cards from the top of their library. Each player puts all artifact, creature, land, and planeswalker cards revealed this way onto the battlefield, then does the same for enchantment cards, then puts all cards revealed this way that weren't put onto the battlefield on the bottom of their library in any order. (Then planeswalk away from this phenomenon.)

Grixis

Blue, black, and/or red creature cards in your graveyard have unearth. The unearth cost is equal to the card's mana cost. (Pay the card's mana cost: Return it to the battlefield. The creature gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)
Whenever chaos ensues, put target creature card from a graveyard onto the battlefield under your control.

Sea of Sand

Players reveal each card they draw.
Whenever a player draws a land card, that player gains 3 life.
Whenever a player draws a nonland card, that player loses 3 life.
Whenever chaos ensues, put target permanent on top of its owner's library.

Interplanar Tunnel

When you encounter Interplanar Tunnel, reveal cards from the top of your planar deck until you reveal five plane cards. Put a plane card from among them on top of your planar deck, then put the rest of the revealed cards on the bottom in a random order. (Then planeswalk away from this phenomenon.)

Kessig

Prevent all combat damage that would be dealt by non-Werewolf creatures.
Whenever chaos ensues, each creature you control gets +2/+2, gains trample, and becomes a Werewolf in addition to its other types until end of turn.

Panopticon

When you planeswalk to Panopticon, draw a card.
At the beginning of your draw step, draw an additional card.
Whenever chaos ensues, draw a card.

Time Distortion

When you encounter Time Distortion, reverse the game's turn order. (For example, if play had proceeded clockwise around the table, it now goes counterclockwise. Then planeswalk away from this phenomenon.)

Orzhova

When you planeswalk away from Orzhova, each player returns all creature cards from their graveyard to the battlefield.
Whenever chaos ensues, for each opponent, exile up to one target creature card from that player's graveyard.

The Great Forest

Each creature assigns combat damage equal to its toughness rather than its power.
Whenever chaos ensues, creatures you control get +0/+2 and gain trample until end of turn.

Goldmeadow

Whenever a land enters, that land's controller creates three 0/1 white Goat creature tokens.
Whenever chaos ensues, create a 0/1 white Goat creature token.

Truga Jungle

All lands have "{T}: Add one mana of any color."
Whenever chaos ensues, reveal the top three cards of your library. Put all land cards revealed this way into your hand and the rest on the bottom of your library in any order.

The Fourth Sphere

At the beginning of your upkeep, sacrifice a nonblack creature.
Whenever chaos ensues, create a 2/2 black Zombie creature token.

Stairs to Infinity

Players have no maximum hand size.
Whenever you roll the planar die, draw a card.
Whenever chaos ensues, reveal the top card of your planar deck. You may put it on the bottom of your planar deck.

Velis Vel

Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Elemental Shamans and an Elemental Spirit are on the battlefield, each gets +2/+2.)
Whenever chaos ensues, target creature gains all creature types until end of turn.

Pools of Becoming

At the beginning of your end step, put the cards in your hand on the bottom of your library in any order, then draw that many cards.
Whenever chaos ensues, reveal the top three cards of your planar deck. Each of the revealed cards' chaos abilities triggers. Then put the revealed cards on the bottom of your planar deck in any order.

Aretopolis

When you planeswalk to Aretopolis and at the beginning of your upkeep, put a scroll counter on Aretopolis, then you gain life equal to the number of scroll counters on it.
When Aretopolis has ten or more scroll counters on it, planeswalk.
Whenever chaos ensues, put a scroll counter on Aretopolis, then draw cards equal to the number of scroll counters on it.

The Hippodrome

All creatures get -5/-0.
Whenever chaos ensues, you may destroy target creature if its power is 0 or less.

Stronghold Furnace

If a source would deal damage to a permanent or player, it deals double that damage instead.
Whenever chaos ensues, Stronghold Furnace deals 1 damage to any target.

Bloodhill Bastion

Whenever a creature enters, it gains double strike and haste until end of turn.
Whenever chaos ensues, exile target nontoken creature you control, then return it to the battlefield under your control.

Celestine Reef

Creatures without flying or islandwalk can't attack.
Whenever chaos ensues, until a player planeswalks, you can't lose the game and your opponents can't win the game.

Mount Keralia

At the beginning of your end step, put a pressure counter on Mount Keralia.
When you planeswalk away from Mount Keralia, it deals damage equal to the number of pressure counters on it to each creature and each planeswalker.
Whenever chaos ensues, prevent all damage that planes named Mount Keralia would deal this game to permanents you control.

Feeding Grounds

Red spells cost {1} less to cast.
Green spells cost {1} less to cast.
Whenever chaos ensues, put X +1/+1 counters on target creature, where X is that creature's mana value.

Grand Ossuary

Whenever a creature dies, its controller distributes a number of +1/+1 counters equal to its power among any number of target creatures they control.
Whenever chaos ensues, each player exiles all creatures they control and creates X 1/1 green Saproling creature tokens, where X is the total power of the creatures they exiled this way. Then planeswalk.

Sokenzan

All creatures get +1/+1 and have haste.
Whenever chaos ensues, untap all creatures that attacked this turn. If it's a main phase, there is an additional combat phase after this phase, followed by an additional main phase.

Cliffside Market

When you planeswalk to Cliffside Market and at the beginning of your upkeep, you may exchange life totals with target player.
Whenever chaos ensues, exchange control of two target permanents that share a card type.

Tazeem

Creatures can't block.
Whenever chaos ensues, draw a card for each land you control.

Planewide Disaster

When you encounter Planewide Disaster, destroy all creatures. (Then planeswalk away from this phenomenon.)

Skybreen

Players play with the top card of their libraries revealed.
Spells that share a card type with the top card of a library can't be cast.
Whenever chaos ensues, target player loses life equal to the number of cards in their hand.

Onakke Catacomb

All creatures are black and have deathtouch.
Whenever chaos ensues, creatures you control get +1/+0 and gain first strike until end of turn.

Tember City

Whenever a player taps a land for mana, Tember City deals 1 damage to that player.
Whenever chaos ensues, each other player sacrifices a nonland permanent of their choice.

Minamo

Whenever a player casts a spell, that player may draw a card.
Whenever chaos ensues, each player may return a blue card from their graveyard to their hand.

Windriddle Palaces

Players play with the top card of their libraries revealed.
You may play lands and cast spells from the top of any player's library.
Whenever chaos ensues, each player mills a card.

Mutual Epiphany

When you encounter Mutual Epiphany, each player draws four cards. (Then planeswalk away from this phenomenon.)

Naya

You may play any number of lands on each of your turns.
Whenever chaos ensues, target red, green, or white creature you control gets +1/+1 until end of turn for each land you control.

Glimmervoid Basin

Whenever a player casts an instant or sorcery spell with a single target, that player copies that spell for each other spell, permanent, card not on the battlefield, and/or player the spell could target. Each copy targets a different one of them.
Whenever chaos ensues, choose target creature. Each player except that creature's controller creates a token that's a copy of that creature.

Isle of Vesuva

Whenever a nontoken creature enters, its controller creates a token that's a copy of that creature.
Whenever chaos ensues, destroy target creature and all other creatures with the same name as that creature.

Reality Shaping

When you encounter Reality Shaping, starting with you, each player may put a permanent card from their hand onto the battlefield. (Then planeswalk away from this phenomenon.)