Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Dread Slaver

Whenever a creature dealt damage by Dread Slaver this turn dies, return it to the battlefield under your control. That creature is a black Zombie in addition to its other colors and types.

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice Hedron Archive: Draw two cards.

Brainstealer Dragon

Flying
At the beginning of your end step, exile the top card of each opponent's library. You may play those cards for as long as they remain exiled. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it.
Whenever a nonland permanent an opponent owns enters the battlefield under your control, they lose life equal to its mana value.

Misshapen Fiend

Nemesis of Reason

Whenever Nemesis of Reason attacks, defending player mills ten cards.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Paranoid Delusions

Target player mills three cards.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Chasm Skulker

Whenever you draw a card, put a +1/+1 counter on Chasm Skulker.
When Chasm Skulker dies, create X 1/1 blue Squid creature tokens with islandwalk, where X is the number of +1/+1 counters on Chasm Skulker. (They can't be blocked as long as defending player controls an Island.)

Glimpse the Unthinkable

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. Talisman of Dominance deals 1 damage to you.

Jwar Isle Refuge

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

Aboleth Spawn

Flash
Ward {2}
Probing Telepathy — Whenever a creature entering under an opponent's control causes a triggered ability of that creature to trigger, you may copy that ability. You may choose new targets for the copy.

In Garruk's Wake

Destroy all creatures you don't control and all planeswalkers you don't control.

Boneshard Slasher

Flying
Threshold — As long as seven or more cards are in your graveyard, Boneshard Slasher gets +2/+2 and has "When Boneshard Slasher becomes the target of a spell or ability, sacrifice it."

Swamp

Leeching Lurker

Lifelink
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Curse of Leeches

Enchant player
As this permanent transforms into Curse of Leeches, attach it to a player.
At the beginning of enchanted player's upkeep, they lose 1 life and you gain 1 life.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Curse of Leeches // Leeching Lurker

Consuming Aberration

Consuming Aberration's power and toughness are each equal to the number of cards in your opponents' graveyards.
Whenever you cast a spell, each opponent reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Worn Powerstone

Worn Powerstone enters tapped.
{T}: Add {C}{C}.

Aetherize

Return all attacking creatures to their owner's hand.

Mindleech Mass

Trample
Whenever Mindleech Mass deals combat damage to a player, you may look at that player's hand. If you do, you may cast a spell from among those cards without paying its mana cost.

Wasp of the Bitter End

Flying
Whenever you cast a Bolas planeswalker spell, you may sacrifice Wasp of the Bitter End. If you do, destroy target creature.

Arcane Signet

Grell Philosopher

Aberrant Tinkering — When Grell Philosopher enters and at the beginning of your upkeep, each Horror you control gains all activated abilities of target artifact an opponent controls until end of turn. You may spend blue mana as though it were mana of any color to activate those abilities.

Aetherspouts

For each attacking creature, its owner puts it on their choice of the top or bottom of their library.

Dimir Signet

Liquimetal Torque

{T}: Add {C}.
{T}: Target nonland permanent becomes an artifact in addition to its other types until end of turn.

Gilded Lotus

Thran Dynamo

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Vebulid

Vebulid enters with a +1/+1 counter on it.
At the beginning of your upkeep, you may put a +1/+1 counter on Vebulid.
When Vebulid attacks or blocks, destroy it at end of combat.

Academy Loremaster

At the beginning of each player's draw step, that player may draw an additional card. If they do, spells they cast this turn cost {2} more to cast.

Exotic Orchard

Crux of Fate

Choose one —
• Destroy all Dragon creatures.
• Destroy all non-Dragon creatures.

Fractured Sanity

Each opponent mills fourteen cards.
Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)
When you cycle Fractured Sanity, each opponent mills four cards.

Grazilaxx, Illithid Scholar

Whenever a creature you control becomes blocked, you may return it to its owner's hand.
Whenever one or more creatures you control deal combat damage to a player, draw a card.

Plague Spitter

At the beginning of your upkeep, Plague Spitter deals 1 damage to each creature and each player.
When Plague Spitter dies, it deals 1 damage to each creature and each player.

Birthday Escape

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Carrion Locust

Flying
When Carrion Locust enters, exile target card from an opponent's graveyard. If it was a creature card, that player loses 1 life.

King Narfi's Betrayal

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Each player mills four cards. Then you may exile a creature or planeswalker card from each graveyard.
II, III — Until end of turn, you may cast spells from among cards exiled with King Narfi's Betrayal, and you may spend mana as though it were mana of any color to cast those spells.

Plague Stinger

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Arvinox, the Mind Flail

Arvinox, the Mind Flail isn't a creature unless you control three or more permanents you don't own.
At the beginning of your end step, exile the bottom card of each opponent's library face down. For as long as those cards remain exiled, you may look at them, you may cast permanent spells from among them, and you may spend mana as though it were mana of any color to cast those spells.

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.

Phyrexian Rager

When Phyrexian Rager enters, you draw a card and you lose 1 life.

Bane Alley Broker

{T}: Draw a card, then exile a card from your hand face down.
You may look at cards exiled with Bane Alley Broker.
{U}{B}, {T}: Return a card exiled with Bane Alley Broker to its owner's hand.

Sol Ring

Nevinyrral's Disk

Nevinyrral's Disk enters tapped.
{1}, {T}: Destroy all artifacts, creatures, and enchantments.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Crypt Lurker

When Crypt Lurker enters, you may sacrifice a creature or discard a creature card. If you do, draw a card.

Basalt Monolith

Basalt Monolith doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{3}: Untap Basalt Monolith.

Temple of Deceit

Temple of Deceit enters tapped.
When Temple of Deceit enters, scry 1.
{T}: Add {U} or {B}.

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Abyssal Gatekeeper

When Abyssal Gatekeeper dies, each player sacrifices a creature of their choice.

Frightcrawler

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Threshold — As long as seven or more cards are in your graveyard, Frightcrawler gets +2/+2 and can't block.

Mithril Coat

Flash
Indestructible
When Mithril Coat enters, attach it to target legendary creature you control.
Equipped creature has indestructible.
Equip {3}

Dauthi Horror

Shadow (This creature can block or be blocked by only creatures with shadow.)
Dauthi Horror can't be blocked by white creatures.

Patchwork Crawler

{2}{U}: Exile target creature card from your graveyard and put a +1/+1 counter on Patchwork Crawler.
Patchwork Crawler has all activated abilities of all creature cards exiled with it.

Island

Sky Diamond

Perplexing Test

Choose one —
• Return all creature tokens to their owners' hands.
• Return all nontoken creatures to their owners' hands.

Chupacabra Echo

Fathomless descent — When Chupacabra Echo enters, target creature an opponent controls gets -X/-X until end of turn, where X is the number of permanent cards in your graveyard.

Dismal Backwater

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

Gríma, Saruman's Footman

Gríma, Saruman's Footman can't be blocked.
Whenever Gríma deals combat damage to a player, that player exiles cards from the top of their library until they exile an instant or sorcery card. You may cast that card without paying its mana cost. Then that player puts the exiled cards that weren't cast this way on the bottom of their library in a random order.

Zellix, Sanity Flayer

Hive Mind — Whenever a player mills one or more creature cards, you create a 1/1 black Horror creature token.
{1}, {T}: Target player mills three cards.
Choose a Background (You can have a Background as a second commander.)

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Mage Hunter

Whenever an opponent casts or copies an instant or sorcery spell, they lose 1 life.

Cleaver Skaab

{3}, {T}, Sacrifice another Zombie: Create two tokens that are copies of the sacrificed creature.

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
Everflowing Chalice enters with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on Everflowing Chalice.

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Hell's Caretaker

{T}, Sacrifice a creature: Return target creature card from your graveyard to the battlefield. Activate only during your upkeep.

Extract from Darkness

Each player mills two cards. Then you put a creature card from a graveyard onto the battlefield under your control.

Dunland Crebain

Flying
When Dunland Crebain enters, amass Orcs 2. (Put two +1/+1 counters on an Army you control. It's also an Orc. If you don't control an Army, create a 0/0 black Orc Army creature token first.)

Dimir Guildgate

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

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Geralf's Mindcrusher

When Geralf's Mindcrusher enters, target player mills five cards.
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Sunken Hollow

({T}: Add {U} or {B}.)
Sunken Hollow enters tapped unless you control two or more basic lands.

Squirming Mass

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

Captain N'ghathrod

Horrors you control have menace.
Whenever a Horror you control deals combat damage to a player, that player mills that many cards.
At the beginning of your end step, choose target artifact or creature card in an opponent's graveyard that was put there from their library this turn. Put it onto the battlefield under your control.

Childhood Horror

Flying
Threshold — As long as seven or more cards are in your graveyard, Childhood Horror gets +2/+2 and can't block.

Psychic Drain

Target player mills X cards and you gain X life.

Hidden Horror

When Hidden Horror enters, sacrifice it unless you discard a creature card.

Dimir Aqueduct

Dimir Aqueduct enters tapped.
When Dimir Aqueduct enters, return a land you control to its owner's hand.
{T}: Add {U}{B}.