Have

Zurzoth, Chaos Rider

Whenever an opponent draws their first card each turn, if it's not their turn, you create a 1/1 red Devil creature token with "When this token dies, it deals 1 damage to any target."
Whenever one or more Devils you control attack one or more players, you and those players each draw a card, then discard a card at random.

Getting

Towashi Guide-Bot

When this creature enters, put a +1/+1 counter on target creature you control.
{4}, {T}: Draw a card. This ability costs {1} less to activate for each modified creature you control. (Equipment, Auras you control, and counters are modifications.)

Spinning Darkness

You may exile the top three black cards of your graveyard rather than pay this spell's mana cost.
Spinning Darkness deals 3 damage to target nonblack creature. You gain 3 life.

Fists of the Demigod

Enchant creature
As long as enchanted creature is black, it gets +1/+1 and has wither. (It deals damage to creatures in the form of -1/-1 counters.)
As long as enchanted creature is red, it gets +1/+1 and has first strike.

You Are Already Dead

Destroy target creature that was dealt damage this turn.
Draw a card.

Vile Mutilator

As an additional cost to cast this spell, sacrifice a creature or enchantment.
Flying, trample
When this creature enters, each opponent sacrifices a nontoken enchantment of their choice, then sacrifices a nontoken creature of their choice.

Nezumi Prowler

Ninjutsu {1}{B} ({1}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
When this creature enters, target creature you control gains deathtouch and lifelink until end of turn.

Sothera, the Supervoid

Whenever a creature you control dies, each opponent chooses a creature they control and exiles it.
At the beginning of your end step, if a player controls no creatures, sacrifice Sothera, then put a creature card exiled with it onto the battlefield under your control with two additional +1/+1 counters on it.

Ogre Slumlord

Whenever another nontoken creature dies, you may create a 1/1 black Rat creature token.
Rats you control have deathtouch.

Brass's Bounty

For each land you control, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Vault of Whispers

Etching of Kumano

Haste
If a creature dealt damage this turn by a source you controlled would die, exile it instead.

Kumano Faces Kakkazan

(As this Saga enters and after your draw step, add a lore counter.)
I — This Saga deals 1 damage to each opponent and each planeswalker they control.
II — When you next cast a creature spell this turn, that creature enters with an additional +1/+1 counter on it.
III — Exile this Saga, then return it to the battlefield transformed under your control.

Kumano Faces Kakkazan // Etching of Kumano

Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

Zof Bloodbog

Zof Consumption

Each opponent loses 4 life and you gain 4 life.

Zof Consumption // Zof Bloodbog

Give In to Violence

Target creature gets +2/+2 and gains lifelink until end of turn.

Smoke Spirits' Aid

For each of up to X target creatures, create a red Aura enchantment token named Smoke Blessing attached to that creature. Those tokens have enchant creature and "When enchanted creature dies, it deals 1 damage to its controller and you create a Treasure token."

Fang Skulkin

{2}: Target black creature gains wither until end of turn. (It deals damage to creatures in the form of -1/-1 counters.)

Inspiring Statuary

Nonartifact spells you cast have improvise. (Your artifacts can help cast those spells. Each artifact you tap after you're done activating mana abilities pays for {1}.)

Kher Keep

{T}: Add {C}.
{1}{R}, {T}: Create a 0/1 red Kobold creature token named Kobolds of Kher Keep.

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Sanguine Morass

This land enters tapped.
{T}: Add {B} or {R}.

Bloodsoaked Insight

This spell costs {1} less to cast for each 1 life your opponents have lost this turn.
Target opponent exiles the top three cards of their library. Until the end of your next turn, you may play those cards. If you cast a spell this way, mana of any type can be spent to cast it.

Bloodsoaked Insight // Sanguine Morass

Kami of Celebration

Whenever a modified creature you control attacks, exile the top card of your library. You may play that card this turn. (Equipment, Auras you control, and counters are modifications.)
Whenever you cast a spell from exile, put a +1/+1 counter on target creature you control.

Terminal Agony

Destroy target creature.
Madness {B}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Footlight Fiend

When this creature dies, it deals 1 damage to any target.

Ogre-Head Helm

Equipped creature gets +2/+2.
Whenever this creature or equipped creature deals combat damage to a player, you may sacrifice it. If you do, discard your hand, then draw three cards.
Reconfigure {3} ({3}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Sire of Insanity

At the beginning of each end step, each player discards their hand.

Keen Duelist

At the beginning of your upkeep, you and target opponent each reveal the top card of your library. You each lose life equal to the mana value of the card revealed by the other player. You each put the card you revealed into your hand.

Descent into Avernus

At the beginning of your upkeep, put two descent counters on this enchantment. Then each player creates X Treasure tokens and this enchantment deals X damage to each player, where X is the number of descent counters on this enchantment.

Supernatural Stamina

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Nether Spirit

At the beginning of your upkeep, if this card is the only creature card in your graveyard, you may return this card to the battlefield.

Widow's Walk

Whenever a creature you control attacks alone, it gets +1/+0 and gains deathtouch 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.)

Derelict Attic

When you unlock this door, you draw two cards and you lose 2 life.
(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.)

Derelict Attic // Widow's Walk

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

Polluted Mire

This land enters tapped.
{T}: Add {B}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Cadaver Lab

When you unlock this door, return target creature card from your graveyard to your hand.
(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.)

Defiled Crypt

Whenever one or more cards leave your graveyard, create a 2/2 black Horror enchantment creature token. This ability triggers only once each 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.)

Defiled Crypt // Cadaver Lab

Death-Rattle Oni

Flash
This spell costs {2} less to cast for each creature that died this turn.
When this creature enters, destroy all other creatures that were dealt damage this turn.

Tide of War

Whenever one or more creatures block, flip a coin. If you win the flip, each blocking creature is sacrificed by its controller. If you lose the flip, each blocked creature is sacrificed by its controller.

Varragoth, Bloodsky Sire

Deathtouch
Boast — {1}{B}: Target player searches their library for a card, then shuffles and puts that card on top. (Activate only if this creature attacked this turn and only once each turn.)

Ironhoof Boar

Trample, haste
Channel — {1}{R}, Discard this card: Target creature gets +3/+1 and gains trample until end of turn.

Ruthless Technomancer

When this creature enters, you may sacrifice another creature you control. If you do, create a number of Treasure tokens equal to that creature's power.
{2}{B}, Sacrifice X artifacts: Return target creature card with power X or less from your graveyard to the battlefield. X can't be 0.

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 token: Add one mana of any color.")

Cutting?

Explosive Singularity

As an additional cost to cast this spell, you may tap any number of untapped creatures you control. This spell costs {1} less to cast for each creature tapped this way.
Explosive Singularity deals 10 damage to any target.

Tainted Peak

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

Appendage Amalgam

Flash
Whenever this creature attacks, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Expensive Taste

Exile the top two cards of target opponent's library face down. You may look at and play those cards for as long as they remain exiled.

adding?

Decadent Dragon

Flying, trample
Whenever this creature attacks, create a Treasure token.

Decadent Dragon // Expensive Taste

Swamp

Painful Quandary

Whenever an opponent casts a spell, that player loses 5 life unless they discard a card.

Kardur, Doomscourge

When Kardur enters, until your next turn, creatures your opponents control attack each combat if able and attack a player other than you if able.
Whenever an attacking creature dies, each opponent loses 1 life and you gain 1 life.

Kumano, Master Yamabushi

{1}{R}: Kumano deals 1 damage to any target.
If a creature dealt damage by Kumano this turn would die, exile it instead.

Necrogen Spellbomb

{B}, Sacrifice this artifact: Target player discards a card.
{1}, Sacrifice this artifact: Draw a card.

Trouble

Trouble deals damage to target player equal to the number of cards in that player's hand.
Fuse (You may cast one or both halves of this card from your hand.)

Toil

Target player draws two cards and loses 2 life.
Fuse (You may cast one or both halves of this card from your hand.)

Toil // Trouble

Fear of Lost Teeth

When this creature dies, it deals 1 damage to any target and you gain 1 life.

Lantern of Revealing

{T}: Add one mana of any color.
{4}, {T}: Look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. If you don't put the card onto the battlefield, you may put it on the bottom of your library.

Heartless Hidetsugu

{T}: Heartless Hidetsugu deals damage to each player equal to half that player's life total, rounded down.

Chandra's Incinerator

This spell costs {X} less to cast, where X is the total amount of noncombat damage dealt to your opponents this turn.
Trample
Whenever a source you control deals noncombat damage to an opponent, this creature deals that much damage to target creature or planeswalker that player controls.

Pitiless Carnage

Sacrifice any number of permanents you control, then draw that many cards.
Plot {1}{B}{B} (You may pay {1}{B}{B} and exile this card from your hand. Cast it as a sorcery on a later turn without paying its mana cost. Plot only as a sorcery.)

Reaper from the Abyss

Flying
Morbid — At the beginning of each end step, if a creature died this turn, destroy target non-Demon creature.

Roadside Reliquary

{T}: Add {C}.
{2}, {T}, Sacrifice this land: Draw a card if you control an artifact. Draw a card if you control an enchantment.

Reassembling Skeleton

{1}{B}: Return this card from your graveyard to the battlefield tapped.

Court of Ire

When this enchantment enters, you become the monarch.
At the beginning of your upkeep, this enchantment deals 2 damage to any target. If you're the monarch, it deals 7 damage instead.

Night Dealings

Whenever a source you control deals damage to another player, put that many theft counters on this enchantment.
{2}{B}{B}, Remove X theft counters from this enchantment: Search your library for a nonland card with mana value X, reveal it, put it into your hand, then shuffle.

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.

Shatter the Source

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Choose one —
• Shatter the Source deals 6 damage to target creature, planeswalker, or battle.
• Destroy target artifact.

Abyssal Harvester

{T}: Exile target creature card from a graveyard that was put there this turn. Create a token that's a copy of it, except it's a Nightmare in addition to its other types. Then exile all other Nightmare tokens you control.

Doom Whisperer

Flying, trample
Pay 2 life: 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.)

Vessel of the All-Consuming

Trample
Whenever this creature deals damage, put a +1/+1 counter on it.
Whenever this creature deals damage to a player, if it has dealt 10 or more damage to that player this turn, they lose the game.

Hidetsugu Consumes All

(As this Saga enters and after your draw step, add a lore counter.)
I — Destroy each nonland permanent with mana value 1 or less.
II — Exile all graveyards.
III — Exile this Saga, then return it to the battlefield transformed under your control.

Hidetsugu Consumes All // Vessel of the All-Consuming

Bronzeplate Boar

Trample
Equipped creature gets +3/+2 and has trample.
Reconfigure {5} ({5}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Shadows of the Past

Whenever a creature dies, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{4}{B}: Each opponent loses 2 life and you gain 2 life. Activate only if there are four or more creature cards in your graveyard.

Burnished Hart

{3}, Sacrifice this creature: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Mayhem Devil

Whenever a player sacrifices a permanent, this creature deals 1 damage to any target.

Malicious Malfunction

All creatures get -2/-2 until end of turn. If a creature would die this turn, exile it instead.

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Fellwar Stone

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

Into the Pit

You may look at the top card of your library any time.
You may cast spells from the top of your library by sacrificing a nonland permanent in addition to paying their other costs.

Searslicer Goblin

Raid — At the beginning of your end step, if you attacked this turn, create a 1/1 red Goblin creature token.

Theater of Horrors

At the beginning of your upkeep, exile the top card of your library.
During your turn, if an opponent lost life this turn, you may play lands and cast spells from among cards exiled with this enchantment.
{3}{R}: This enchantment deals 1 damage to target opponent or planeswalker.

Mark of the Vampire

Enchant creature
Enchanted creature gets +2/+2 and has lifelink.

Audacious Reshapers

{T}, Sacrifice an artifact: Reveal cards from the top of your library until you reveal an artifact card. Put that card onto the battlefield and the rest on the bottom of your library in a random order. This creature deals damage to you equal to the number of cards revealed this way.

Automated Artificer

{T}: Add {C}. Spend this mana only to activate an ability or cast an artifact spell.

Blade of the Oni

Menace
Equipped creature has base power and toughness 5/5, has menace, and is a black Demon in addition to its other colors and types.
Reconfigure {2}{B}{B} ({2}{B}{B}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Arcane Signet

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

Komainu Battle Armor

Menace
Equipped creature gets +2/+2 and has menace.
Whenever this creature or equipped creature deals combat damage to a player, goad each creature that player controls.
Reconfigure {4} ({4}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Atsushi, the Blazing Sky

Flying, trample
When Atsushi dies, choose one —
• Exile the top two cards of your library. Until the end of your next turn, you may play those cards.
• Create three Treasure tokens.

Scrap Welder

{T}, Sacrifice an artifact with mana value X: Return target artifact card with mana value less than X from your graveyard to the battlefield. It gains haste until end of turn.

Shivan Gorge

{T}: Add {C}.
{2}{R}, {T}: Shivan Gorge deals 1 damage to each opponent.

Assassin's Ink

This spell costs {1} less to cast if you control an artifact and {1} less to cast if you control an enchantment.
Destroy target creature or planeswalker.

Witch's Cottage

({T}: Add {B}.)
This land enters tapped unless you control three or more other Swamps.
When this land enters untapped, you may put target creature card from your graveyard on top of your library.

Prisoner's Dilemma

Each opponent secretly chooses silence or snitch, then the choices are revealed. If each opponent chose silence, Prisoner's Dilemma deals 4 damage to each of them. If each opponent chose snitch, Prisoner's Dilemma deals 8 damage to each of them. Otherwise, Prisoner's Dilemma deals 12 damage to each opponent who chose silence.
Flashback {5}{R}{R}