Abstergo Entertainment

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{3}, {T}, Exile Abstergo Entertainment: Return up to one target historic card from your graveyard to your hand, then exile all graveyards. (Artifacts, legendaries, and Sagas are historic.)

Buried Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice Buried Ruin: Return target artifact card from your graveyard to your hand.

Toxrill, the Corrosive

At the beginning of each end step, put a slime counter on each creature you don't control.
Creatures you don't control get -1/-1 for each slime counter on them.
Whenever a creature you don't control with a slime counter on it dies, create a 1/1 black Slug creature token.
{U}{B}, Sacrifice a Slug: Draw a card.

Fireball

This spell costs {1} more to cast for each target beyond the first.
Fireball deals X damage divided evenly, rounded down, among any number of targets.

Arcane Signet

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

Marchesa, the Black Rose

Dethrone (Whenever this creature attacks the player with the most life or tied for most life, put a +1/+1 counter on it.)
Other creatures you control have dethrone.
Whenever a creature you control with a +1/+1 counter on it dies, return that card to the battlefield under your control at the beginning of the next end step.

Incinerator of the Guilty

Flying, trample
Whenever Incinerator of the Guilty deals combat damage to a player, you may collect evidence X. When you do, Incinerator of the Guilty deals X damage to each creature and planeswalker that player controls. (To collect evidence X, exile cards with total mana value X or greater from your graveyard.)

Blasphemous Act

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

Sol Ring

Crackle with Power

Crackle with Power deals five times X damage to each of up to X targets.

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.

Anger of the Gods

Anger of the Gods deals 3 damage to each creature. If a creature dealt damage this way would die this turn, exile it instead.

Basalt Monolith

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

In Garruk's Wake

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

Immolating Gyre

Immolating Gyre deals X damage to each creature and planeswalker you don't control, where X is the number of instant and sorcery cards in your graveyard.

Scheming Symmetry

Choose two target players. Each of them searches their library for a card, then shuffles and puts that card on top.

Ashnod's Altar

Plague Wind

Destroy all creatures you don't control. They can't be regenerated.

Star of Extinction

Destroy target land. Star of Extinction deals 20 damage to each creature and each planeswalker.

Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Toxic Deluge

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

Staff of Eden, Vault's Key

When Staff of Eden, Vault's Key enters, put target legendary permanent card not named Staff of Eden, Vault's Key from a graveyard onto the battlefield under your control.
{T}: Draw a card for each permanent you control but don't own.

Final Act

Choose one or more —
• Destroy all creatures.
• Destroy all planeswalkers.
• Destroy all battles.
• Exile all graveyards.
• Each opponent loses all counters.

Storm's Wrath

Storm's Wrath deals 4 damage to each creature and each planeswalker.

Thought Vessel

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

Thassa, Deep-Dwelling

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of your end step, exile up to one other target creature you control, then return that card to the battlefield under your control.
{3}{U}: Tap another target creature.

Showstopping Surprise

Choose target creature you control. Turn it face up if it's face down. Then it deals damage equal to its power to each other creature.

Talisman of Dominance

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

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Profane Tutor

Suspend 2—{1}{B} (Rather than cast this card from your hand, pay {1}{B} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
Search your library for a card, put that card into your hand, then shuffle.

Power Word Kill

Destroy target non-Angel, non-Demon, non-Devil, non-Dragon creature.

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.

Crippling Fear

Choose a creature type. Creatures that aren't of the chosen type get -3/-3 until end of turn.

Maskwood Nexus

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Negate

Sweltering Suns

Sweltering Suns deals 3 damage to each creature.
Cycling {3} ({3}, Discard this card: Draw a card.)

Dimir Signet

Counterspell

Mizzium Mortars

Mizzium Mortars deals 4 damage to target creature you don't control.
Overload {3}{R}{R}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Talisman of Indulgence

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

Golden Demise

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
All creatures get -2/-2 until end of turn. If you have the city's blessing, instead only creatures your opponents control get -2/-2 until end of turn.

Satoru, the Infiltrator

Menace
Whenever Satoru, the Infiltrator and/or one or more other nontoken creatures you control enter, if none of them were cast or no mana was spent to cast them, draw a card.

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Brotherhood's End

Choose one —
• Brotherhood's End deals 3 damage to each creature and each planeswalker.
• Destroy all artifacts with mana value 3 or less.

Pyroclasm

Pyroclasm deals 2 damage to each creature.

Don Andres, the Renegade

Each creature you control but don't own gets +2/+2, has menace and deathtouch, and is a Pirate in addition to its other types.
Whenever you cast a noncreature spell you don't own, create two tapped Treasure tokens.

The Beast, Deathless Prince

When you cast this spell, gain control of target creature until end of turn. Untap it. It gains menace and haste until end of turn.
The Beast enters tapped with six stun counters on it. (If it would become untapped, remove a stun counter from it instead.)
Whenever a creature deals combat damage to its owner, untap The Beast and 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.

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.

Wishclaw Talisman

Wishclaw Talisman enters with three wish counters on it.
{1}, {T}, Remove a wish counter from Wishclaw Talisman: Search your library for a card, put it into your hand, then shuffle. An opponent gains control of Wishclaw Talisman. Activate only during your turn.

Forsaken Monument

Colorless creatures you control get +2/+2.
Whenever you tap a permanent for {C}, add an additional {C}.
Whenever you cast a colorless spell, you gain 2 life.

Starstorm

Starstorm deals X damage to each creature.
Cycling {3} ({3}, Discard this card: Draw a card.)

Vandalblast

Destroy target artifact you don't control.
Overload {4}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Hostile Takeover

Up to one target creature has base power and toughness 1/1 until end of turn. Up to one other target creature has base power and toughness 4/4 until end of turn. Then Hostile Takeover deals 3 damage to each creature.

Izzet Signet

Mahadi, Emporium Master

At the beginning of your end step, create a Treasure token for each creature that died this turn. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

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.

Talisman of Creativity

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

Diabolic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Thieving Amalgam

At the beginning of each opponent's upkeep, you manifest the top card of that player's 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 a creature you control but don't own dies, its owner loses 2 life and you gain 2 life.

Rakdos Signet

Bitter Triumph

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

They Came from the Pipes

When They Came from the Pipes 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.

Kozilek, the Broken Reality

When you cast this spell, up to two target players each manifest two cards from their hands. For each card manifested this way, you draw a card. (To manifest a card, 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.)
Other colorless creatures you control get +3/+2.

Maestros Ascendancy

Once during each of your turns, you may cast an instant or sorcery spell from your graveyard by sacrificing a creature in addition to paying its other costs. If a spell cast this way would be put into your graveyard, exile it instead.

Blood Money

Destroy all creatures. For each nontoken creature destroyed this way, you create a tapped Treasure token.

Decree of Pain

Destroy all creatures. They can't be regenerated. Draw a card for each creature destroyed this way.
Cycling {3}{B}{B} ({3}{B}{B}, Discard this card: Draw a card.)
When you cycle Decree of Pain, all creatures get -2/-2 until end of turn.

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.)

The Horus Heresy

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — For each opponent, gain control of up to one target nonlegendary creature that player controls for as long as The Horus Heresy remains on the battlefield.
II — Draw a card for each creature you control but don't own.
III — Starting with you, each player chooses a creature. Destroy each creature chosen this way.

End the Festivities

End the Festivities deals 1 damage to each opponent and each creature and planeswalker they control.

Cybership

Flying
Whenever Cybership deals combat damage to a player, put the top two cards of that player's library onto the battlefield face down under your control. They're 2/2 Cyberman artifact creatures.
Crew 4

Shoot the Sheriff

Destroy target non-outlaw creature. (Assassins, Mercenaries, Pirates, Rogues, and Warlocks are outlaws. Everyone else is fair game.)

Kindred Dominance

Choose a creature type. Destroy all creatures that aren't of the chosen type.

Loyal Inventor

Vigilance
When Loyal Inventor 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.