Ob Nixilis, Captive Kingpin - Built around Kederekt Parasite, Razorkin Needlehead and Kessig Flamebreather

Kederekt Parasite

Creature — Horror

$8.29

Whenever an opponent draws a card, if you control a red permanent, you may have this creature deal 1 damage to that player.

Razorkin Needlehead

Creature — Human Assassin

$5.4

This creature has first strike during your turn. Whenever an opponent draws a card, this creature deals 1 damage to them.

Prosper, Tome-Bound

Legendary Creature — Tiefling Warlock

$4.99

Deathtouch Mystic Arcanum — At the beginning of your end step, exile the top card of your library. Until the end of your next turn, you may play that card. Pact Boon — Whenever you play a card from exile, create a Treasure token.

Kessig Flamebreather

Creature — Human Shaman

$3.07

Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent.

Coruscation Mage

Creature — Otter Wizard

$1.61

Offspring {2} (You may pay an additional {2} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.) Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent.

Firebrand Archer

Creature — Human Archer

$0.27

Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent.

Scrawling Crawler

Artifact Creature — Phyrexian Construct

$3.43

At the beginning of your upkeep, each player draws a card. Whenever an opponent draws a card, that player loses 1 life.

Casey Jones, Back Alley Brute

Legendary Creature — Human Berserker

$0.32

Menace Whenever Casey Jones attacks, put a +1/+1 counter on target attacking creature. Whenever you put one or more +1/+1 counters on a creature you control, Casey Jones deals that much damage to target opponent.

Walking Ballista

Artifact Creature — Construct

$5.27

This creature enters with X +1/+1 counters on it. {4}: Put a +1/+1 counter on this creature. Remove a +1/+1 counter from this creature: It deals 1 damage to any target.

Glaring Fleshraker

Creature — Eldrazi Drone

$1.24

Whenever you cast a colorless spell, create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this token: Add {C}." Whenever another colorless creature you control enters, this creature deals 1 damage to each opponent.

Avalanche of Sector 7

Legendary Creature — Human Rebel

$0.21

Menace Avalanche of Sector 7's power is equal to the number of artifacts your opponents control. Whenever an opponent activates an ability of an artifact they control, Avalanche of Sector 7 deals 1 damage to that player.

Soot Imp

Creature — Imp

$1.26

Flying Whenever a player casts a nonblack spell, that player loses 1 life.

Mayhem Devil

Creature — Devil

$0.3

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

Party Thrasher

Creature — Lizard Wizard

$0.62

Noncreature spells you cast from exile have convoke. (Each creature you tap while casting a noncreature spell from exile pays for {1} or one mana of that creature's color.) At the beginning of your first main phase, you may discard a card. If you do, exile the top two cards of your library, then choose one of them. You may play that card this turn.

Hexing Squelcher

Creature — Goblin Sorcerer

$19.24

This spell can't be countered. Ward—Pay 2 life. Spells you control can't be countered. Other creatures you control have "Ward—Pay 2 life."

Reckless Fireweaver

Creature — Human Artificer

$0.4

Whenever an artifact you control enters, this creature deals 1 damage to each opponent.

Simian Spirit Guide

Creature — Ape Spirit

$3.2

Exile this card from your hand: Add {R}.

Blood Seeker

Creature — Vampire Shaman

$0.23

Whenever a creature an opponent controls enters, you may have that player lose 1 life.

Dualcaster Mage

Creature — Human Wizard

$3.56

Flash When this creature enters, copy target instant or sorcery spell. You may choose new targets for the copy.

Fate Unraveler

Enchantment Creature — Hag

$2.85

Whenever an opponent draws a card, this creature deals 1 damage to that player.

Thermo-Alchemist

Creature — Human Shaman

$0.17

Defender {T}: This creature deals 1 damage to each opponent. Whenever you cast an instant or sorcery spell, untap this creature.

Blood Artist

Creature — Vampire

$2.78

Whenever this creature or another creature dies, target player loses 1 life and you gain 1 life.

Gleeful Arsonist

Creature — Human Wizard

$5.72

Whenever an opponent casts a noncreature spell, this creature deals damage equal to its power to that player. 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.)

Stormfist Crusader

Creature — Human Knight

$0.38

Menace At the beginning of your upkeep, each player draws a card and loses 1 life.

Storm-Kiln Artist

Creature — Dwarf Shaman

$1.7

This creature gets +1/+0 for each artifact you control. Magecraft — Whenever you cast or copy an instant or sorcery spell, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Goblin Engineer

Creature — Goblin Artificer

$8.82

When this creature enters, you may search your library for an artifact card, put it into your graveyard, then shuffle. {R}, {T}, Sacrifice an artifact: Return target artifact card with mana value 3 or less from your graveyard to the battlefield.

Creeping Bloodsucker

Creature — Vampire

$4.82

At the beginning of your upkeep, this creature deals 1 damage to each opponent. You gain life equal to the damage dealt this way.

Imperial Recruiter

Creature — Human Advisor

$12.32

When this creature enters, search your library for a creature card with power 2 or less, reveal it, put it into your hand, then shuffle.

Rampaging Ferocidon

Creature — Dinosaur

$1.87

Menace Players can't gain life. Whenever another creature enters, this creature deals 1 damage to that creature's controller.

Disciple of the Vault

Creature — Human Cleric

$0.9

Whenever an artifact is put into a graveyard from the battlefield, you may have target opponent lose 1 life.

Valgavoth, Harrower of Souls

Legendary Creature — Elder Demon

$23.85

Flying Ward—Pay 2 life. Whenever an opponent loses life for the first time during each of their turns, put a +1/+1 counter on Valgavoth and draw a card.

Kardur, Doomscourge

Legendary Creature — Demon Berserker

$0.46

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.

Professional Face-Breaker

Creature — Human Warrior

$4.89

Menace Whenever one or more creatures you control deal combat damage to a player, create a Treasure token. Sacrifice a Treasure: Exile the top card of your library. You may play that card this turn.

Iridescent Vinelasher

Creature — Lizard Assassin

$1.19

Offspring {2} (You may pay an additional {2} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.) Landfall — Whenever a land you control enters, this creature deals 1 damage to target opponent.

Nightshade Harvester

Creature — Elf Shaman

$0.36

Whenever a land an opponent controls enters, that player loses 1 life. Put a +1/+1 counter on this creature.

Weftstalker Ardent

Creature — Drix Artificer

$3.77

Whenever another creature or artifact you control enters, this creature deals 1 damage to each opponent. Warp {R} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)

Pain Distributor

Creature — Devil Citizen

$5.25

Menace Whenever a player casts their first spell each turn, they create a Treasure token. Whenever an artifact an opponent controls is put into a graveyard from the battlefield, this creature deals 1 damage to that player.

Laelia, the Blade Reforged

Legendary Creature — Spirit Warrior

$0.33

Haste Whenever Laelia attacks, exile the top card of your library. You may play that card this turn. Whenever one or more cards are put into exile from your library and/or your graveyard, put a +1/+1 counter on Laelia.

Electro, Assaulting Battery

Legendary Creature — Human Villain

$4.18

Flying You don't lose unspent red mana as steps and phases end. Whenever you cast an instant or sorcery spell, add {R}. When Electro leaves the battlefield, you may pay {X}. When you do, he deals X damage to target player.

Deadpool, Trading Card

Legendary Creature — Mutant Mercenary Hero

$15.14

As Deadpool enters, you may exchange his text box and another creature's. At the beginning of your upkeep, you lose 3 life. {3}, Sacrifice this creature: Each other player draws a card.

Persistent Constrictor

Creature — Zombie Snake

$11.84

At the beginning of each opponent's upkeep, they lose 1 life and you put a -1/-1 counter on up to one target creature they control. Persist (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.)

Alicia Masters, Skilled Sculptor

Legendary Creature — Human Artificer

$0.25

At the beginning of combat on your turn, if you've cast a noncreature spell this turn, create a Treasure token. Sense the Good — At the beginning of your end step, each player gains control of all creatures they own.

Dark Ritual

Instant

$0.44

Add {B}{B}{B}.

Rending Volley

Instant

$0.22

This spell can't be countered. Rending Volley deals 4 damage to target white or blue creature.

Lava Dart

Instant

$0.86

Lava Dart deals 1 damage to any target. Flashback—Sacrifice a Mountain. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Deadly Rollick

Instant

$27.34

If you control a commander, you may cast this spell without paying its mana cost. Exile target creature.

Cabal Ritual

Instant

$14.55

Add {B}{B}{B}. Threshold — Add {B}{B}{B}{B}{B} instead if there are seven or more cards in your graveyard.

Pyretic Ritual

Instant

$6.23

Add {R}{R}{R}.

Red Elemental Blast

Instant

$1.91

Choose one — • Counter target blue spell. • Destroy target blue permanent.

Pyroblast

Instant

$3.37

Choose one — • Counter target spell if it's blue. • Destroy target permanent if it's blue.

Desperate Ritual

Instant — Arcane

$5.81

Add {R}{R}{R}. Splice onto Arcane {1}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

The Last Agni Kai

Instant

$2.14

Target creature you control fights target creature an opponent controls. If the creature the opponent controls is dealt excess damage this way, add that much {R}. Until end of turn, you don't lose unspent red mana as steps and phases end.

Seething Song

Instant

$6.78

Add {R}{R}{R}{R}{R}.

Culling the Weak

Instant

$6.84

As an additional cost to cast this spell, sacrifice a creature. Add {B}{B}{B}{B}.

Ad Nauseam

Instant

$9.89

Reveal the top card of your library and put that card into your hand. You lose life equal to its mana value. You may repeat this process any number of times.

Delayed Blast Fireball

Instant

$14.94

Delayed Blast Fireball deals 2 damage to each opponent and each creature they control. If this spell was cast from exile, it deals 5 damage to each opponent and each creature they control instead. Foretell {4}{R}{R} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Grapeshot

Sorcery

$0.27

Grapeshot deals 1 damage to any target. Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Blasphemous Act

Sorcery

$0.72

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

End the Festivities

Sorcery

$0.94

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

Light Up the Stage

Sorcery

$0.28

Spectacle {R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.) Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Unstable Amulet

Artifact

$0.23

When this artifact enters, you get {E}{E} (two energy counters). Whenever you cast a spell from anywhere other than your hand, this artifact deals 1 damage to each opponent. {T}, Pay {E}{E}: Exile the top card of your library. You may play it until you exile another card with this artifact.

Agatha's Soul Cauldron

Legendary Artifact

$37.9

You may spend mana as though it were mana of any color to activate abilities of creatures you control. Creatures you control with +1/+1 counters on them have all activated abilities of all creature cards exiled with Agatha's Soul Cauldron. {T}: Exile target card from a graveyard. When a creature card is exiled this way, put a +1/+1 counter on target creature you control.

Shadow of the Goblin

Enchantment

$0.8

Unreliable Visions — At the beginning of your first main phase, discard a card. If you do, draw a card. Undying Vengeance — Whenever you play a land or cast a spell from anywhere other than your hand, this enchantment deals 1 damage to each opponent.

All Will Be One

Enchantment

$11.26

Whenever you put one or more counters on a permanent or player, this enchantment deals that much damage to target opponent, creature an opponent controls, or planeswalker an opponent controls.

Shivan Gorge

Legendary Land

$1.04

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

Emergence Zone

Land

$4.05

{T}: Add {C}. {1}, {T}, Sacrifice this land: You may cast spells this turn as though they had flash.

Leechridden Swamp

Land — Swamp

$0.73

({T}: Add {B}.) This land enters tapped. {B}, {T}: Each opponent loses 1 life. Activate only if you control two or more black permanents.

Bojuka Bog

Land

$0.99

This land enters tapped. When this land enters, exile target player's graveyard. {T}: Add {B}.

Sunscorched Desert

Land — Desert

$0.35

When this land enters, it deals 1 damage to target player or planeswalker. {T}: Add {C}.

Rogue's Passage

Land

$0.29

{T}: Add {C}. {4}, {T}: Target creature can't be blocked this turn.

Takenuma, Abandoned Mire

Legendary Land

$10.68

{T}: Add {B}. Channel — {3}{B}, Discard this card: Mill three cards, then return a creature or planeswalker card from your graveyard to your hand. This ability costs {1} less to activate for each legendary creature you control.

Great Furnace

Artifact Land

$2.53

{T}: Add {R}.

Barbarian Ring

Land

$0.26

{T}: Add {R}. This land deals 1 damage to you. Threshold — {R}, {T}, Sacrifice this land: It deals 2 damage to any target. Activate only if there are seven or more cards in your graveyard.

Sokenzan, Crucible of Defiance

Legendary Land

$2.71

{T}: Add {R}. Channel — {3}{R}, Discard this card: Create two 1/1 colorless Spirit creature tokens. They gain haste until end of turn. This ability costs {1} less to activate for each legendary creature you control.

Witch's Clinic

Land

$3.88

{T}: Add {C}. {2}, {T}: Target commander gains lifelink until end of turn.

Piranha Marsh

Land

$0.28

This land enters tapped. When this land enters, target player loses 1 life. {T}: Add {B}.

Command Beacon

Land

$8.34

{T}: Add {C}. {T}, Sacrifice this land: Put your commander into your hand from the command zone.

Reliquary Tower

Land

$4.19

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

Cabal Pit

Land

$0.31

{T}: Add {B}. This land deals 1 damage to you. Threshold — {B}, {T}, Sacrifice this land: Target creature gets -2/-2 until end of turn. Activate only if there are seven or more cards in your graveyard.

Arena of Glory

Land

$7.63

This land enters tapped unless you control a Mountain. {T}: Add {R}. {R}, {T}, Exert this land: Add {R}{R}. If any of that mana is spent on a creature spell, it gains haste until end of turn. (An exerted permanent won't untap during your next untap step.)