Kothophed, Soul Hoarder

Flying
Whenever a permanent owned by another player is put into a graveyard from the battlefield, you draw a card and you lose 1 life.

Swamp

Dream Devourer

Each nonland card in your hand without foretell has foretell. Its foretell cost is equal to its mana cost reduced by {2}. (During your turn, you may pay {2} and exile it from your hand face down. Cast it on a later turn for its foretell cost.)
Whenever you foretell a card, Dream Devourer gets +2/+0 until end of turn.

Underworld Hermit

When Underworld Hermit enters, create a number of 1/1 green Squirrel creature tokens equal to your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Rogue's Passage

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

Archfiend of Depravity

Flying
At the beginning of each opponent's end step, that player chooses up to two creatures they control, then sacrifices the rest.

Dread Shade

{B}: Dread Shade gets +1/+1 until end of turn.

Ob Nixilis of the Black Oath

+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.

Painful Quandary

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

Murder

Epicure of Blood

Whenever you gain life, each opponent loses 1 life.

Feed the Swarm

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

Cast Down

Endling

{B}: Endling gains menace until end of turn.
{B}: Endling gains deathtouch until end of turn.
{B}: Endling gains undying until end of turn. (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.)
{1}: Endling gets +1/-1 or -1/+1 until end of turn.

Ob Nixilis Reignited

+1: You draw a card and you lose 1 life.
−3: Destroy target creature.
−8: Target opponent gets an emblem with "Whenever a player draws a card, you lose 2 life."

Witch's Vengeance

Creatures of the creature type of your choice get -3/-3 until end of turn.

Gonti, Lord of Luxury

Deathtouch
When Gonti, Lord of Luxury enters, look at the top four cards of target opponent's library, exile one of them face down, then put the rest on the bottom of that library in a random order. You may cast that card for as long as it remains exiled, and mana of any type can be spent to cast that spell.

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Typhoid Rats

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Lord of the Void

Flying
Whenever Lord of the Void deals combat damage to a player, exile the top seven cards of that player's library, then put a creature card from among them onto the battlefield under your control.

Squelching Leeches

Squelching Leeches's power and toughness are each equal to the number of Swamps you control.

Myojin of Grim Betrayal

Myojin of Grim Betrayal enters with an indestructible counter on it if you cast it from your hand.
Remove an indestructible counter from Myojin of Grim Betrayal: Put onto the battlefield under your control all creature cards in all graveyards that were put there from anywhere this turn.

Vat of Rebirth

Whenever another artifact or creature you control is put into a graveyard from the battlefield, put an oil counter on Vat of Rebirth.
{2}{B}, {T}, Remove four oil counters from Vat of Rebirth: Return target creature card from your graveyard to the battlefield. Activate only as a sorcery.

Hero's Downfall

Sign in Blood

Target player draws two cards and loses 2 life.

Demon of Dark Schemes

Flying
When Demon of Dark Schemes enters, all other creatures get -2/-2 until end of turn.
Whenever another creature dies, you get {E} (an energy counter).
{2}{B}, Pay {E}{E}{E}{E}: Put target creature card from a graveyard onto the battlefield under your control tapped.

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Foul Renewal

Return target creature card from your graveyard to your hand. Target creature gets -X/-X until end of turn, where X is the toughness of the card returned this way.

Seizan, Perverter of Truth

At the beginning of each player's upkeep, that player loses 2 life and draws two cards.

Lolth, Spider Queen

Whenever a creature you control dies, put a loyalty counter on Lolth, Spider Queen.
0: You draw a card and you lose 1 life.
−3: Create two 2/1 black Spider creature tokens with menace and reach.
−8: You get an emblem with "Whenever an opponent is dealt combat damage by one or more creatures you control, if that player lost less than 8 life this turn, they lose life equal to the difference."

Quicksilver Amulet

{4}, {T}: You may put a creature card from your hand onto the battlefield.

Underworld Dreams

Whenever an opponent draws a card, Underworld Dreams deals 1 damage to that player.

Sol Ring

Dark Ritual

Rune-Scarred Demon

Flying
When this creature enters, search your library for a card, put it into your hand, then shuffle.

Defiant Bloodlord

Flying
Whenever you gain life, target opponent loses that much life.

Prism Ring

As Prism Ring enters, choose a color.
Whenever you cast a spell of the chosen color, you gain 1 life.

Bad Moon

Demonlord Belzenlok

Flying, trample
When Demonlord Belzenlok enters, 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.

Banehound

Ob Nixilis, the Fallen

Landfall — Whenever a land you control enters, you may have target player lose 3 life. If you do, put three +1/+1 counters on Ob Nixilis, the Fallen.

Nightmare

Flying (This creature can't be blocked except by creatures with flying or reach.)
Nightmare's power and toughness are each equal to the number of Swamps you control.

Corrupt

Corrupt deals damage to any target equal to the number of Swamps you control. You gain life equal to the damage dealt this way.

Sanguine Bond

Whenever you gain life, target opponent loses that much life.

Drown in Sorrow

All creatures get -2/-2 until end of turn. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Thran Dynamo

Hollowborn Barghest

At the beginning of your upkeep, if you have no cards in hand, each opponent loses 2 life.
At the beginning of each opponent's upkeep, if that player has no cards in hand, they lose 2 life.

Go for the Throat

Eye of Vecna

When Eye of Vecna enters, you draw a card and you lose 2 life.
At the beginning of your upkeep, you may pay {2}. If you do, you draw a card and you lose 2 life.

Zulaport Cutthroat

Whenever Zulaport Cutthroat or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Dark Prophecy

Whenever a creature you control dies, you draw a card and you lose 1 life.

Liliana's Reaver

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.

Read the Bones

Scry 2, then draw two cards. You lose 2 life. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Thought Vessel

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

Breach the Multiverse

Each player mills ten cards. For each player, choose a creature or planeswalker card in that player's graveyard. Put those cards onto the battlefield under your control. Then each creature you control becomes a Phyrexian in addition to its other types.

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Mirrodin Avenged

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

Luxior, Giada's Gift

Equipped creature gets +1/+1 for each counter on it.
Equipped permanent isn't a planeswalker and is a creature in addition to its other types. (Loyalty abilities can still be activated.)
Equip planeswalker {1}
Equip {3}

Diabolic Tutor

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

Eater of Hope

Flying
{B}, Sacrifice another creature: Regenerate Eater of Hope.
{2}{B}, Sacrifice two other creatures: Destroy target creature.