Mountain

Sulfur Falls

This land enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Roshan, Hidden Magister

Other creatures you control are Assassins in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
Face-down creatures you control have menace.
Whenever a permanent you control is turned face up, you draw a card and you lose 1 life.

Counterspell

The Master, Multiplied

Myriad
The "legend rule" doesn't apply to creature tokens you control.
Triggered abilities you control can't cause you to sacrifice or exile creature tokens you control.

Arno Dorian

Deathtouch
Other Assassins you control get +2/+0.
Disguise {B}{R} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)

Ravenous Amulet

{1}, {T}, Sacrifice a creature: Draw a card and put a soul counter on this artifact. Activate only as a sorcery.
{4}, {T}, Sacrifice this artifact: Each opponent loses life equal to the number of soul counters on this artifact.

Irenicus's Vile Duplication

Create a token that's a copy of target creature you control, except the token has flying and it isn't legendary.

Fear of Impostors

Flash
When this creature enters, counter target spell. Its controller manifests dread. (That player looks at the top two cards of their library, then puts one onto the battlefield face down as a 2/2 creature and the other into their graveyard. If it's a creature card, it can be turned face up any time for its mana cost.)

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Oversold Cemetery

At the beginning of your upkeep, if you have four or more creature cards in your graveyard, you may return target creature card from your graveyard to your hand.

Jacob Frye

Partner with Evie Frye (When this creature enters, target player may put Evie into their hand from their library, then shuffle.)
Whenever one or more Assassins you control deal combat damage to a player, exile up to one target Assassin card or card with freerunning from your graveyard. If you do, copy it. You may cast the copy.

Ashnod's Altar

Missy

Whenever another nonartifact creature dies, return it to the battlefield under your control face down and tapped. It's a 2/2 Cyberman artifact creature.
At the beginning of your end step, each opponent faces a villainous choice — Each artifact creature you control deals 1 damage to that opponent, or you draw a card and chaos ensues.

Silumgar Assassin

Creatures with power greater than this creature's power can't block it.
Megamorph {2}{B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)
When this creature is turned face up, destroy target creature with power 3 or less an opponent controls.

Glitch Interpreter

When this creature enters, if you control no face-down permanents, return this creature to its owner's hand and manifest dread.
Whenever one or more colorless creatures you control deal combat damage to a player, draw a card.

Evolving Wilds

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

Stratus Dancer

Flying
Megamorph {1}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)
When this creature is turned face up, counter target instant or sorcery spell.

Etrata, Deadly Fugitive

Deathtouch
Face-down creatures you control have "{2}{U}{B}: Turn this creature face up. If you can't, exile it, then you may cast the exiled card without paying its mana cost."
Whenever an Assassin you control deals combat damage to an opponent, cloak the top card of that player's library.

Arcane Signet

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

Gallifrey Council Chamber

When Gallifrey Council Chamber enters, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a Time Lord or Alien spell or activate an ability of a Time Lord or Alien.

Rakdos Signet

Cyberman Patrol

Artifact creatures you control have afflict 3. (Whenever a creature with afflict 3 becomes blocked, defending player loses 3 life.)

Skirk Alarmist

Haste
{T}: Turn target face-down creature you control face up. At the beginning of the next end step, sacrifice it.

Evie Frye

Partner with Jacob Frye (When this creature enters, target player may put Jacob into their hand from their library, then shuffle.)
{1}, {T}: Draw a card, then discard a card. When you discard a creature card this way, target creature you control can't be blocked this turn.

Frostboil Snarl

As this land enters, you may reveal an Island or Mountain card from your hand. If you don't, this land enters tapped.
{T}: Add {U} or {R}.

Ballad of the Black Flag

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after IV.)
I, II, III — Mill three cards. You may put a historic card from among them into your hand. (Artifacts, legendaries, and Sagas are historic.)
IV — Historic spells you cast this turn cost {2} less to cast.

Expose the Culprit

Choose one or both —
• Turn target face-down creature face up.
• Exile any number of face-up creatures you control with disguise in a face-down pile, shuffle that pile, then cloak them. (To cloak a card, put it onto the battlefield face down as a 2/2 creature with ward {2}. Turn it face up any time for its mana cost if it's a creature card.)

Grixis Panorama

{T}: Add {C}.
{1}, {T}, Sacrifice this land: Search your library for a basic Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

They Came from the Pipes

When this enchantment enters, manifest dread twice. (To manifest dread, look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)
Whenever a face-down creature you control enters, draw a card.

The Master, Gallifrey's End

Make Them Pay — Whenever a nontoken artifact creature you control dies, you may exile it. If you do, choose an opponent with the most life among your opponents. That player faces a villainous choice — They lose 4 life, or you create a token that's a copy of that card.

Loyal Inventor

Vigilance
When this creature enters, you may search your library for an artifact card, reveal it, then shuffle. Put that card into your hand if you control an Assassin. Otherwise, put that card on top of your library.

Notion Rain

Surveil 2, then draw two cards. Notion Rain deals 2 damage to you. (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.)

Terramorphic Expanse

Fugitive Codebreaker

Prowess, haste
Disguise {5}{R}. This cost is reduced by {1} for each instant and sorcery card in your graveyard. (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)
When this creature is turned face up, discard your hand, then draw three cards.

Innocuous Rat

When this creature dies, manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Island

Quick Study

Cyber Conversion

Turn target creature face down. It's a 2/2 Cyberman artifact creature.

Myriad Landscape

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

Refute

Counter target spell. Draw a card, then discard a card.

Izzet Signet

Death in Heaven

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Target player mills two cards, then exiles their graveyard.
III — Put all creature cards exiled with this enchantment onto the battlefield face down under your control. They're 2/2 Cyberman artifact creatures.

Ugin's Mastery

Whenever you cast a colorless creature spell, manifest the top card of your library. (Put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)
Whenever you attack with creatures with total power 6 or greater, you may turn a face-down creature you control face up.

Pyrotechnic Performer

Disguise {R} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)
Whenever this creature or another creature you control is turned face up, that creature deals damage equal to its power to each opponent.

Swamp

Twist Reality

Choose one —
• Counter target spell.
• Manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Dimir Signet

Ruthless Ripper

Deathtouch
Morph—Reveal a black card in your hand. (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When this creature is turned face up, target player loses 2 life.

Slimy Aquarium

When you unlock this door, manifest dread, then put a +1/+1 counter on that creature.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Underwater Tunnel

When you unlock this door, 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.)
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Underwater Tunnel // Slimy Aquarium

The Master, Formed Anew

Body Thief — When you cast this spell, you may exile a creature you control and put a takeover counter on it.
You may have The Master enter as a copy of a creature card in exile with a takeover counter on it.

Tunnel of Hate

Whenever you attack, target attacking creature gains double strike until end of turn.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Ticket Booth

When you unlock this door, manifest dread.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Ticket Booth // Tunnel of Hate

Infernal Grasp

Destroy target creature. You lose 2 life.

Terminate

Destroy target creature. It can't be regenerated.

Gloomlake Verge

{T}: Add {U}.
{T}: Add {B}. Activate only if you control an Island or a Swamp.

Become Anonymous

Exile target nontoken creature you own and the top two cards of your library in a face-down pile, shuffle that pile, then cloak those cards. They enter tapped. (To cloak a card, put it onto the battlefield face down as a 2/2 creature with ward {2}. Turn it face up any time for its mana cost if it's a creature card.)

Shivan Reef

{T}: Add {C}.
{T}: Add {U} or {R}. This land deals 1 damage to you.

Dark Ritual

Scroll of Fate

{T}: Manifest a card from your hand. (Put that card onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

Disturbing Mirth

When this enchantment enters, you may sacrifice another enchantment or creature. If you do, draw two cards.
When you sacrifice this enchantment, manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Cult Conscript

This creature enters tapped.
{1}{B}: Return this card from your graveyard to the battlefield. Activate only if a non-Skeleton creature died under your control this turn.

The Master, Mesmerist

{T}: Target creature an opponent controls with power less than or equal to The Master's power gains skulk until end of turn. Goad it. (A creature with skulk can't be blocked by creatures with greater power.)
Whenever a creature with skulk deals combat damage to one of your opponents, put a +1/+1 counter on The Master and draw a card.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Command Tower

Negate

Exit Specialist

This creature can't be blocked by creatures with power 3 or greater.
Disguise {1}{U} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)
When this creature is turned face up, return another target creature to its owner's hand.

Ashad, the Lone Cyberman

The first nonlegendary artifact spell you cast each turn has casualty 2. (As you cast it, you may sacrifice a creature with power 2 or greater. When you do, copy it. A copy of an artifact spell becomes a token.)
Whenever you sacrifice another creature, put a +1/+1 counter on Ashad.

Cybermat

Skulk (This creature can't be blocked by creatures with greater power.)
Whenever this creature attacks and isn't blocked, it gets +X/+0 until end of turn, where X is the number of attacking artifact creatures.

Diabolic Intent

As an additional cost to cast this spell, sacrifice a creature.
Search your library for a card, put that card into your hand, then shuffle.

Sol Ring

Viconia, Drow Apostate

At the beginning of your upkeep, if there are four or more creature cards in your graveyard, return a creature card at random from your graveyard to your hand.
Choose a Background (You can have a Background as a second commander.)

Cybermen Squadron

Nonlegendary artifact creatures you control have myriad. (Whenever a creature with myriad attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

The Cyber-Controller

When The Cyber-Controller enters, each opponent mills X cards. Put all creature cards milled this way onto the battlefield face down under your control. They're 2/2 Cyberman artifact creatures.
Other artifact creatures you control get +1/+1.

Boltbender

Disguise {1}{R} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)
When this creature is turned face up, you may choose new targets for any number of other spells and/or abilities.

Bitter Triumph

As an additional cost to cast this spell, discard a card or pay 3 life.
Destroy target creature or planeswalker.

Blazemire Verge

{T}: Add {B}.
{T}: Add {R}. Activate only if you control a Swamp or a Mountain.

Ixidron

As this creature enters, turn all other nontoken creatures face down. (They're 2/2 creatures.)
Ixidron's power and toughness are each equal to the number of face-down creatures on the battlefield.