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.

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.

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.

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.

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.

The Caldaia

Creature spells you cast from your hand have blitz {3}. (If you cast a spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)
Whenever chaos ensues, return target creature card from your graveyard to your hand.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Akoum

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

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.