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.

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.)

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.

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.

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.)

Strixhaven

Instant and sorcery spells players cast have demonstrate. (Whenever a player casts an instant or sorcery spell, they may copy it. If they do, they choose an opponent to also copy it. Players may choose new targets for their copies.)
Whenever chaos ensues, return up to one target instant or sorcery card from a graveyard to its owner's hand.

Gavony

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

The Fertile Lands of Saulvinia

Whenever a player taps a land for mana, that player adds one mana of any type that land produced.
Whenever chaos ensues, reveal cards from the top of your planar deck until you reveal a plane card. Chaos ensues on that plane. Then put all cards revealed this way on the bottom of your planar deck in any order.

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.

Mutual Epiphany

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

Krosa

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

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.

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.)

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.

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.

Enigma Ridges

When you planeswalk to Enigma Ridges, each player who controls fewer lands than the player who controls the most lands searches their library for a number of basic land cards less than or equal to the difference, reveals them, puts them into their hand, then shuffles.
Whenever chaos ensues, draw a card, then you may put a land card from your hand onto the battlefield.

Norn's Seedcore

When you planeswalk to Norn's Seedcore, chaos ensues.
Whenever chaos ensues, reveal cards from the top of your planar deck until you reveal a plane card. Planeswalk to it, except don't planeswalk away from any plane. Put the rest of the revealed cards on the bottom of your planar deck in any order.

Valor's Reach

Whenever your team attacks with exactly two creatures, those creatures gain double strike until end of turn.
Whenever chaos ensues, untap up to two target creatures your team controls. If it's a main phase, there is an additional combat phase after this phase, followed by an additional main phase.

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.

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.