You can't win the game and your opponents can't lose the game.
6 /
6
--
Arcane Lighthouse
Land
{T}: Add {C}.
{1}, {T}: Until end of turn, creatures your opponents control lose hexproof and shroud and can't have hexproof or shroud.
{4}{B}{B}
Archetype of Finality
Enchantment Creature - Gorgon
Creatures you control have deathtouch.
Creatures your opponents control lose deathtouch and can't have or gain deathtouch.
2 /
3
{3}{B}{B}
Archfiend of Depravity
Creature - Demon
Flying
At the beginning of each opponent's end step, that player chooses up to two creatures they control, then sacrifices the rest.
5 /
4
{9}
Artisan of Kozilek
Creature - Eldrazi
When you cast this spell, you may return target creature card from your graveyard to the battlefield.
Annihilator 2 (Whenever this creature attacks, defending player sacrifices two permanents.)
10 /
9
{6}{B}{B}
Avatar of Woe
Creature - Avatar
If there are ten or more creature cards total in all graveyards, this spell costs {6} less to cast.
Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
{T}: Destroy target creature. It can't be regenerated.
6 /
5
--
Barren Moor
Land
Barren Moor enters tapped.
{T}: Add {B}.
Cycling {B} ({B}, Discard this card: Draw a card.)
{3}{B}{B}
Beacon of Unrest
Sorcery
Put target artifact or creature card from a graveyard onto the battlefield under your control. Shuffle Beacon of Unrest into its owner's library.
{X}{B}{B}
Black Sun's Zenith
Sorcery
Put X -1/-1 counters on each creature. Shuffle Black Sun's Zenith into its owner's library.
{3}{B}{B}
Bloodgift Demon
Creature - Demon
Flying
At the beginning of your upkeep, target player draws a card and loses 1 life.
5 /
4
--
Bojuka Bog
Land
Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.
{5}{B}{B}
Butcher of Malakir
Creature - Vampire Warrior
Flying
Whenever Butcher of Malakir or another creature you control dies, each opponent sacrifices a creature.
5 /
4
{6}
Caged Sun
Artifact
As Caged Sun enters the battlefield, choose a color.
Creatures you control of the chosen color get +1/+1.
Whenever a land's ability causes you to add one or more mana of the chosen color, add one additional mana of that color.
{3}{B}{B}
Conspiracy
Enchantment
As Conspiracy enters the battlefield, choose a creature type.
Creatures you control are the chosen type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{5}{B}
Corrupt
Sorcery
Corrupt deals damage to any target equal to the number of Swamps you control. You gain life equal to the damage dealt this way.
{3}{B}
Crypt Ghast
Creature - Spirit
Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever you tap a Swamp for mana, add an additional {B}.
2 /
2
--
Crypt of Agadeem
Land
Crypt of Agadeem enters the battlefield tapped.
{T}: Add {B}.
{2}, {T}: Add {B} for each black creature card in your graveyard.
{3}{B}{B}
Demon of Wailing Agonies
Creature - Demon
Flying
Lieutenant -- As long as you control your commander, Demon of Wailing Agonies gets +2/+2 and has "Whenever Demon of Wailing Agonies deals combat damage to a player, that player sacrifices a creature."
4 /
4
{4}{B}{B}
Demonlord Belzenlok
Legendary Creature - Elder Demon
Flying, trample
When Demonlord Belzenlok enters the battlefield, exile cards from the top of your library until you exile a nonland card, then put that card into your hand. If the card's mana value is 4 or greater, repeat this process. Demonlord Belzenlok deals 1 damage to you for each card put into your hand this way.
6 /
6
{3}{B}
Disciple of Bolas
Creature - Human Wizard
When Disciple of Bolas enters the battlefield, sacrifice another creature. You gain X life and draw X cards, where X is that creature's power.
2 /
1
{3}{B}{B}
Drana, Kalastria Bloodchief
Legendary Creature - Vampire Shaman
Flying
{X}{B}{B}: Target creature gets -0/-X until end of turn and Drana, Kalastria Bloodchief gets +X/+0 until end of turn.
4 /
4
{2}{B}{B}
Dread Return
Sorcery
Return target creature card from your graveyard to the battlefield.
Flashback--Sacrifice three creatures. (You may cast this card from your graveyard for its flashback cost. Then exile it.)
{B}{B}{B}
Dread Shade
Creature - Shade
{B}: Dread Shade gets +1/+1 until end of turn.
3 /
3
{2}
Endless Atlas
Artifact
{2}, {T}: Draw a card. Activate only if you control three or more lands with the same name.
{3}{B}
Erebos, God of the Dead
Legendary Enchantment Creature - God
Indestructible
As long as your devotion to black is less than five, Erebos isn't a creature. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)
Your opponents can't gain life.
{1}{B}, Pay 2 life: Draw a card.
5 /
7
--
Everglades
Land
Everglades enters the battlefield tapped.
When Everglades enters the battlefield, sacrifice it unless you return an untapped Swamp you control to its owner's hand.
{T}: Add {C}{B}.
{X}{B}{B}
Exsanguinate
Sorcery
Each opponent loses X life. You gain life equal to the life lost this way.
{2}{B}
Flesh Carver
Creature - Human Wizard
Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
{1}{B}, Sacrifice another creature: Put two +1/+1 counters on Flesh Carver.
When Flesh Carver dies, create an X/X black Horror creature token, where X is Flesh Carver's power.
2 /
2
--
Ghost Quarter
Land
{T}: Add {C}.
{T}, Sacrifice Ghost Quarter: Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.
{3}{B}{B}
Ghoulcaller Gisa
Legendary Creature - Human Wizard
{B}, {T}, Sacrifice another creature: Create X 2/2 black Zombie creature tokens, where X is the sacrificed creature's power.
3 /
4
{5}{B}{B}
Grave Betrayal
Enchantment
Whenever a creature you don't control dies, return it to the battlefield under your control with an additional +1/+1 counter on it at the beginning of the next end step. That creature is a black Zombie in addition to its other colors and types.
{4}{B}{B}
Grave Titan
Creature - Giant
Deathtouch
Whenever Grave Titan enters the battlefield or attacks, create two 2/2 black Zombie creature tokens.
6 /
6
{4}{B}{B}
Harvester of Souls
Creature - Demon
Deathtouch
Whenever another nontoken creature dies, you may draw a card.
5 /
5
{7}{B}{B}
In Garruk's Wake
Sorcery
Destroy all creatures you don't control and all planeswalkers you don't control.
{4}{B}
Infernal Offering
Sorcery
Choose an opponent. You and that player each sacrifice a creature. Each player who sacrificed a creature this way draws two cards.
Choose an opponent. Return a creature card from your graveyard to the battlefield, then that player returns a creature card from their graveyard to the battlefield.
{2}
Jet Medallion
Artifact
Black spells you cast cost {1} less to cast.
{2}{B}{B}
Josu Vess, Lich Knight
Legendary Creature - Zombie Knight
Kicker {5}{B} (You may pay an additional {5}{B} as you cast this spell.)
Menace
When Josu Vess, Lich Knight enters the battlefield, if it was kicked, create eight 2/2 black Zombie Knight creature tokens with menace.
4 /
5
{4}
Lashwrithe
Artifact - Equipment
Living weapon (When this Equipment enters the battlefield, create a 0/0 black Phyrexian Germ creature token, then attach this to it.)
Equipped creature gets +1/+1 for each Swamp you control.
Equip {B/P}{B/P} ({B/P} can be paid with either {B} or 2 life.)
--
Leechridden Swamp
Land - Swamp
({T}: Add {B}.)
Leechridden Swamp enters the battlefield tapped.
{B}, {T}: Each opponent loses 1 life. Activate only if you control two or more black permanents.
{3}{B}{B}
Liliana's Contract
Enchantment
When Liliana's Contract enters the battlefield, you draw four cards and you lose 4 life.
At the beginning of your upkeep, if you control four or more Demons with different names, you win the game.
{4}{B}
Magus of the Coffers
Creature - Human Wizard
{2}, {T}: Add {B} for each Swamp you control.
4 /
4
{B}{B}
Malicious Affliction
Instant
Morbid -- When you cast this spell, if a creature died this turn, you may copy Malicious Affliction and may choose a new target for the copy.
Destroy target nonblack creature.
--
Memorial to Folly
Land
Memorial to Folly enters the battlefield tapped.
{T}: Add {B}.
{2}{B}, {T}, Sacrifice Memorial to Folly: Return target creature card from your graveyard to your hand.
{3}{B}{B}{B}
Midnight Banshee
Creature - Spirit
Wither (This deals damage to creatures in the form of -1/-1 counters.)
At the beginning of your upkeep, put a -1/-1 counter on each nonblack creature.
5 /
5
{2}{B}{B}
Mutilate
Sorcery
All creatures get -1/-1 until end of turn for each Swamp you control.
--
Myriad Landscape
Land
Myriad Landscape enters the battlefield 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.
{B}{B}
Nantuko Shade
Creature - Insect Shade
{B}: Nantuko Shade gets +1/+1 until end of turn.
2 /
1
{4}{B}{B}{B}
Necromantic Selection
Sorcery
Destroy all creatures, then return a creature card put into a graveyard this way to the battlefield under your control. It's a black Zombie in addition to its other colors and types. Exile Necromantic Selection.
{3}{B}{B}{B}
Necropolis Regent
Creature - Vampire
Flying
Whenever a creature you control deals combat damage to a player, put that many +1/+1 counters on it.
6 /
5
{1}
Nihil Spellbomb
Artifact
{T}, Sacrifice Nihil Spellbomb: Exile target player's graveyard.
When Nihil Spellbomb is put into a graveyard from the battlefield, you may pay {B}. If you do, draw a card.
{3}{B}{B}
Ob Nixilis of the Black Oath
Legendary Planeswalker - Nixilis
+2: Each opponent loses 1 life. You gain life equal to the life lost this way.
-2: Create a 5/5 black Demon creature token with flying. You lose 2 life.
-8: You get an emblem with "{1}{B}, Sacrifice a creature: You gain X life and draw X cards, where X is the sacrificed creature's power."
Ob Nixilis of the Black Oath can be your commander.
L:
3
{4}{B}{B}
Ob Nixilis, Unshackled
Legendary Creature - Demon
Flying, trample
Whenever an opponent searches their library, that player sacrifices a creature and loses 10 life.
Whenever another creature dies, put a +1/+1 counter on Ob Nixilis, Unshackled.
4 /
4
{5}{B}{B}
Overseer of the Damned
Creature - Demon
Flying
When Overseer of the Damned enters the battlefield, you may destroy target creature.
Whenever a nontoken creature an opponent controls dies, create a tapped 2/2 black Zombie creature token.
5 /
5
{X}{B}{B}
Profane Command
Sorcery
Choose two --
• Target player loses X life.
• Return target creature card with mana value X or less from your graveyard to the battlefield.
• Target creature gets -X/-X until end of turn.
• Up to X target creatures gain fear until end of turn. (They can't be blocked except by artifact creatures and/or black creatures.)
{2}{B}{B}{B}
Promise of Power
Sorcery
Choose one --
• You draw five cards and you lose 5 life.
• Create an X/X black Demon creature token with flying, where X is the number of cards in your hand.
Entwine {4} (Choose both if you pay the entwine cost.)
{3}{B}{B}{B}
Reaper from the Abyss
Creature - Demon
Flying
Morbid -- At the beginning of each end step, if a creature died this turn, destroy target non-Demon creature.
6 /
6
--
Reliquary Tower
Land
You have no maximum hand size.
{T}: Add {C}.
{5}{B}{B}
Sheoldred, Whispering One
Legendary Creature - Phyrexian Praetor
Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
At the beginning of your upkeep, return target creature card from your graveyard to the battlefield.
At the beginning of each opponent's upkeep, that player sacrifices a creature.
6 /
6
{3}{B}{B}
Sidisi, Undead Vizier
Legendary Creature - Zombie Naga
Deathtouch
Exploit (When this creature enters the battlefield, 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.
4 /
6
{1}{B}
Skirsdag High Priest
Creature - Human Cleric
Morbid -- {T}, Tap two untapped creatures you control: Create a 5/5 black Demon creature token with flying. Activate only if a creature died this turn.
1 /
2
{1}
Sol Ring
Artifact
{T}: Add {C}{C}.
{1}{B}{B}
Sudden Spoiling
Instant
Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Until end of turn, creatures target player controls lose all abilities and have base power and toughness 0/2.
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
{4}{B}
The Eldest Reborn
Enchantment - Saga
(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I -- Each opponent sacrifices a creature or planeswalker.
II -- Each opponent discards a card.
III -- Put target creature or planeswalker card from a graveyard onto the battlefield under your control.
{2}
Thornbite Staff
Kindred Artifact - Shaman Equipment
Equipped creature has "{2}, {T}: This creature deals 1 damage to any target" and "Whenever a creature dies, untap this creature."
Whenever a Shaman creature enters, you may attach Thornbite Staff to it.
Equip {4}
{X}{B}{B}
Torment of Hailfire
Sorcery
Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent or discards a card.
{B}
Tragic Slip
Instant
Target creature gets -1/-1 until end of turn.
Morbid -- That creature gets -13/-13 until end of turn instead if a creature died this turn.
Sacrifice Vampire Hexmage: Remove all counters from target permanent.
2 /
1
{2}{B}
Victimize
Sorcery
Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.
{3}{B}{B}{B}
Visara the Dreadful
Legendary Creature - Gorgon
Flying
{T}: Destroy target creature. It can't be regenerated.
5 /
5
{B}{B}
Withered Wretch
Creature - Zombie Cleric
{1}: Exile target card from a graveyard.
2 /
2
{5}{B}
Xathrid Gorgon
Creature - Gorgon
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
{2}{B}, {T}: Put a petrification counter on target creature. It gains defender and becomes a colorless artifact in addition to its other types. Its activated abilities can't be activated. (A creature with defender can't attack.)
3 /
6
{4}{B}
Yawgmoth's Vile Offering
Legendary Sorcery
(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Put up to one target creature or planeswalker card from a graveyard onto the battlefield under your control. Destroy up to one target creature or planeswalker. Exile Yawgmoth's Vile Offering.