Chronic Flooding

Enchant land
Whenever enchanted land becomes tapped, its controller mills three cards.

Sultai Ascendancy

At the beginning of your upkeep, 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.)

Woebringer Demon

Flying
At the beginning of each player's upkeep, that player sacrifices a creature of their choice. If the player can't, sacrifice Woebringer Demon.

Slum Reaper

When Slum Reaper enters, each player sacrifices a creature of their choice.

Fleshbag Marauder

When Fleshbag Marauder enters, each player sacrifices a creature of their choice.

Caustic Caterpillar

{1}{G}, Sacrifice Caustic Caterpillar: Destroy target artifact or enchantment.

Sidisi, Undead Vizier

Deathtouch
Exploit (When this creature enters, you may sacrifice a creature.)
When Sidisi, Undead Vizier exploits a creature, you may search your library for a card, put it into your hand, then shuffle.

Seal of Primordium

Sacrifice Seal of Primordium: Destroy target artifact or enchantment.

Corpse Connoisseur

When Corpse Connoisseur enters, you may search your library for a creature card, put that card into your graveyard, then shuffle.
Unearth {3}{B} ({3}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Jwar Isle Refuge

Jwar Isle Refuge enters tapped.
When Jwar Isle Refuge enters, you gain 1 life.
{T}: Add {U} or {B}.

Spore Frog

Sacrifice Spore Frog: Prevent all combat damage that would be dealt this turn.

Perpetual Timepiece

{T}: Mill two cards.
{2}, Exile Perpetual Timepiece: Shuffle any number of target cards from your graveyard into your library.

World Shaper

Whenever World Shaper attacks, you may mill three cards.
When World Shaper dies, return all land cards from your graveyard to the battlefield tapped.

Nyx Weaver

Reach
At the beginning of your upkeep, mill two cards. (Put the top two cards of your library into your graveyard.)
{1}{B}{G}, Exile Nyx Weaver: Return target card from your graveyard to your hand.

Secrets of the Dead

Whenever you cast a spell from your graveyard, draw a card.

Siren Stormtamer

Flying
{U}, Sacrifice Siren Stormtamer: Counter target spell or ability that targets you or a creature you control.

Plaguecrafter

When Plaguecrafter enters, each player sacrifices a creature or planeswalker of their choice. Each player who can't discards a card.

Kaya's Ghostform

Enchant creature or planeswalker you control
When enchanted permanent dies or is put into exile, return that card to the battlefield under your control.

Dreamborn Muse

At the beginning of each player's upkeep, that player mills X cards, where X is the number of cards in their hand.

Possessed Portal

If a player would draw a card, that player skips that draw instead.
At the beginning of each end step, each player sacrifices a permanent of their choice unless they discard a card.

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.

Stinkweed Imp

Flying
Whenever Stinkweed Imp deals combat damage to a creature, destroy that creature.
Dredge 5 (If you would draw a card, you may mill five cards instead. If you do, return this card from your graveyard to your hand.)

Dismal Backwater

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {U} or {B}.