Dispersal

Each opponent returns a nonland permanent they control with the highest mana value among permanents they control to its owner's hand, then discards a card.

Discovery

Surveil 2, then draw a card. (To surveil 2, look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Discovery // Dispersal

Island

Disinformation Campaign

When Disinformation Campaign enters, you draw a card and each opponent discards a card.
Whenever you surveil, return Disinformation Campaign to its owner's hand.

Nightveil Predator

Flying, deathtouch
Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Quench

Counter target spell unless its controller pays {2}.

Sinister Sabotage

Counter target spell.
Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Thought Erasure

Target opponent reveals their hand. You choose a nonland card from it. That player discards that card.
Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Dimir Guildgate

Dimir Guildgate enters tapped.
{T}: Add {U} or {B}.

Walk the Plank

Heartless Act

Choose one —
• Destroy target creature with no counters on it.
• Remove up to three counters from target creature.

Negate

Submerged Boneyard

Submerged Boneyard enters tapped.
{T}: Add {U} or {B}.

Cast Down

Dismal Backwater

Dismal Backwater enters tapped.
When Dismal Backwater enters, you gain 1 life.
{T}: Add {U} or {B}.

The Eldest Reborn

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Each opponent sacrifices a creature or planeswalker of their choice.
II — Each opponent discards a card.
III — Put target creature or planeswalker card from a graveyard onto the battlefield under your control.

Swamp

Cry of the Carnarium

All creatures get -2/-2 until end of turn. Exile all creature cards in all graveyards that were put there from the battlefield this turn. If a creature would die this turn, exile it instead.