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
--
Barren Moor
Land
Barren Moor enters the battlefield 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 the battlefield tapped.
When Bojuka Bog enters the battlefield, 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.
{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
{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.)
{4}{B}
Eliminate the Competition
Sorcery
As an additional cost to cast this spell, sacrifice X creatures.
Destroy X target creatures.
{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}.
{4}{B}
Exquisite Blood
Enchantment
Whenever an opponent loses life, you gain that much life.
{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}
Grip of Desolation
Instant
Devoid (This card has no color.)
Exile target creature and target land.
{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.
{5}{B}{B}
Kalitas, Bloodchief of Ghet
Legendary Creature - Vampire Warrior
{B}{B}{B}, {T}: Destroy target creature. If that creature dies this way, create a black Vampire creature token. Its power is equal to that creature's power and its toughness is equal to that creature's toughness.
5 /
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.
{2}{B}{B}
Liliana's Reaver
Creature - Zombie
Deathtouch
Whenever Liliana's Reaver deals combat damage to a player, that player discards a card and you create a tapped 2/2 black Zombie creature token.
4 /
3
{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.
{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.
{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
{1}{B}{B}
Phyrexian Crusader
Creature - Phyrexian Zombie Knight
First strike, protection from red and from white
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
2 /
2
--
Polluted Mire
Land
Polluted Mire enters the battlefield tapped.
{T}: Add {B}.
Cycling {2} ({2}, Discard this card: Draw a card.)
{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.)
{4}{B}
Raving Dead
Creature - Zombie
Deathtouch
At the beginning of combat on your turn, choose an opponent at random. Raving Dead attacks that player this combat if able.
Whenever Raving Dead deals combat damage to a player, that player loses half their life, rounded down.
2 /
6
{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}.
{3}{B}{B}
Sanguine Bond
Enchantment
Whenever you gain life, target opponent loses that much life.
{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}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
{2}
Swiftfoot Boots
Artifact - Equipment
Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}
{2}
Thornbite Staff
Tribal 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 the battlefield, you may attach Thornbite Staff to it.
Equip {4}
{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.
Each land is a Swamp in addition to its other land types.
{B}{B}
Vampire Hexmage
Creature - Vampire Shaman
First strike
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
{3}{B}{B}{B}
Xathrid Demon
Creature - Demon
Flying, trample
At the beginning of your upkeep, sacrifice a creature other than Xathrid Demon, then each opponent loses life equal to the sacrificed creature's power. If you can't sacrifice a creature, tap Xathrid Demon and you lose 7 life.
7 /
7
{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.