Troll of Khazad-dûm

This creature can't be blocked except by three or more creatures.
Swampcycling {1} ({1}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)

Death's Shadow

This creature gets -X/-X, where X is your life total.

Undead Butler

When this creature enters, mill three cards. (Put the top three cards of your library into your graveyard.)
When this creature dies, you may exile it. When you do, return target creature card from your graveyard to your hand.

Bog Witch

Corpses of the Lost

Skeletons you control get +1/+0 and have haste.
When this enchantment enters, create a 2/2 black Skeleton Pirate creature token.
At the beginning of your end step, if you descended this turn, you may pay 1 life. If you do, return this enchantment to its owner's hand. (You descended if a permanent card was put into your graveyard from anywhere.)

Soldevi Adnate

{T}, Sacrifice a black or artifact creature: Add an amount of {B} equal to the sacrificed creature's mana value.

Void Beckoner

Deathtouch
Cycling {2}{B} ({2}{B}, Discard this card: Draw a card.)
When you cycle this card, put a deathtouch counter on target creature you control.

Ulamog's Dreadsire

Vigilance
Ward—Sacrifice a permanent with mana value 1 or greater.
{T}: Create a 10/10 colorless Eldrazi creature token.

Rotting Regisaur

At the beginning of your upkeep, discard a card.

Ancient Stone Idol

Flash
This spell costs {1} less to cast for each attacking creature.
Trample
When this creature dies, create a 6/12 colorless Construct artifact creature token with trample.

Xu-Ifit, Osteoharmonist

{T}: Return target creature card from your graveyard to the battlefield. It's a Skeleton in addition to its other types and has no abilities. Activate only as a sorcery.

Demon of Death's Gate

You may pay 6 life and sacrifice three black creatures rather than pay this spell's mana cost.
Flying, trample

Millikin

{T}, Mill a card: Add {C}. (To mill a card, put the top card of your library into your graveyard.)

Buried Alive

Search your library for up to three creature cards, put them into your graveyard, then shuffle.

Shadowheart, Dark Justiciar

{1}{B}, {T}, Sacrifice another creature: Draw X cards, where X is that creature's power.
Choose a Background (You can have a Background as a second commander.)

Gisa, the Hellraiser

Ward—{2}, Pay 2 life.
Skeletons and Zombies you control get +1/+1 and have menace.
Whenever you commit a crime, create two tapped 2/2 blue and black Zombie Rogue creature tokens. This ability triggers only once each turn. (Targeting opponents, anything they control, and/or cards in their graveyards is a crime.)

Devouring Strossus

Flying, trample
At the beginning of your upkeep, sacrifice a creature.
Sacrifice a creature: Regenerate this creature.

Have

Valgavoth, Terror Eater

Flying, lifelink
Ward—Sacrifice three nonland permanents.
If a card you didn't control would be put into an opponent's graveyard from anywhere, exile it instead.
During your turn, you may play cards exiled with Valgavoth. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

Syr Konrad, the Grim

Whenever another creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves your graveyard, Syr Konrad deals 1 damage to each opponent.
{1}{B}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Pathrazer of Ulamog

Annihilator 3 (Whenever this creature attacks, defending player sacrifices three permanents of their choice.)
This creature can't be blocked except by three or more creatures.

Death Baron

Skeletons you control and other Zombies you control get +1/+1 and have deathtouch. (Any amount of damage they deal to a creature is enough to destroy it.)

Gray Merchant of Asphodel

When this creature 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.)

Dark Ritual

Stitcher's Supplier

When this creature enters or dies, mill three cards. (Put the top three cards of your library into your graveyard.)

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Ghoulcaller Gisa

{B}, {T}, Sacrifice another creature: Create X 2/2 black Zombie creature tokens, where X is the sacrificed creature's power.

Disciple of Bolas

When this creature enters, sacrifice another creature. You gain X life and draw X cards, where X is that creature's power.

Vile Entomber

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When this creature enters, search your library for a card, put that card into your graveyard, then shuffle.

Kuro, Pitlord

At the beginning of your upkeep, sacrifice Kuro unless you pay {B}{B}{B}{B}.
Pay 1 life: Target creature gets -1/-1 until end of turn.