Skithiryx, the Blight Dragon

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{B}: Skithiryx, the Blight Dragon gains haste until end of turn.
{B}{B}: Regenerate Skithiryx.

Binding the Old Gods

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Destroy target nonland permanent an opponent controls.
II — Search your library for a Forest card, put it onto the battlefield tapped, then shuffle.
III — Creatures you control gain deathtouch until end of turn.

Emperor of Bones

At the beginning of combat on your turn, exile up to one target card from a graveyard.
{1}{B}: Adapt 2.
Whenever one or more +1/+1 counters are put on Emperor of Bones, put a creature card exiled with Emperor of Bones onto the battlefield under your control with a finality counter on it. It gains haste. Sacrifice it at the beginning of the next end step.

Bad Moon

Golgari Grave-Troll

Golgari Grave-Troll enters with a +1/+1 counter on it for each creature card in your graveyard.
{1}, Remove a +1/+1 counter from Golgari Grave-Troll: Regenerate Golgari Grave-Troll.
Dredge 6 (If you would draw a card, you may mill six cards instead. If you do, return this card from your graveyard to your hand.)

Mournwillow

Haste
Delirium — When Mournwillow enters, if there are four or more card types among cards in your graveyard, creatures with power 2 or less can't block this turn.

Spawning Pool

Spawning Pool enters tapped.
{T}: Add {B}.
{1}{B}: Spawning Pool becomes a 1/1 black Skeleton creature with "{B}: Regenerate this creature" until end of turn. It's still a land. (If it regenerates, the next time it would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Assassin's Trophy

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Bone Splinters

As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature.

Culling Ritual

Destroy each nonland permanent with mana value 2 or less. Add {B} or {G} for each permanent destroyed this way.

Temple of Malady

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {B} or {G}.

Ghastly Death Tyrant

When Ghastly Death Tyrant enters, choose one —
• Disintegration Ray — Destroy target enchantment an opponent controls. You lose life equal to its mana value.
• Death Ray — Creatures you control gain deathtouch until end of turn.

Snow-Covered Swamp

Deathreap Ritual

Morbid — At the beginning of each end step, if a creature died this turn, you may draw a card.

Unclaimed Territory

As Unclaimed Territory enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

Skeletal Vampire

Flying
When Skeletal Vampire enters, create two 1/1 black Bat creature tokens with flying.
{3}{B}{B}, Sacrifice a Bat: Create two 1/1 black Bat creature tokens with flying.
Sacrifice a Bat: Regenerate Skeletal Vampire.

Meren of Clan Nel Toth

Whenever another creature you control dies, you get an experience counter.
At the beginning of your end step, choose target creature card in your graveyard. If that card's mana value is less than or equal to the number of experience counters you have, return it to the battlefield. Otherwise, put it into your hand.

Golgari Rot Farm

Golgari Rot Farm enters tapped.
When Golgari Rot Farm enters, return a land you control to its owner's hand.
{T}: Add {B}{G}.

Snow-Covered Forest

Slitherbore Pathway

Darkbore Pathway

Darkbore Pathway // Slitherbore Pathway

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.)

Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Crippling Fear

Choose a creature type. Creatures that aren't of the chosen type get -3/-3 until end of turn.

Altar's Reap

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Putrefy

Destroy target artifact or creature. It can't be regenerated.

Woodland Chasm

({T}: Add {B} or {G}.)
Woodland Chasm enters tapped.

Skeletal Crocodile

Undergrowth Stadium

Undergrowth Stadium enters tapped unless you have two or more opponents.
{T}: Add {B} or {G}.

Wretched Bonemass

Wretched Bonemass's power and toughness are each equal to the total power of the exiled cards used to craft it.
Wretched Bonemass has flying as long as an exiled card used to craft it has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, protection, reach, trample, and vigilance.

Altar of the Wretched

When Altar of the Wretched enters, you may sacrifice a nontoken creature. If you do, draw X cards, then mill X cards, where X is that creature's power.
Craft with one or more creatures {2}{B}{B}
{2}{B}: Return Altar of the Wretched from your graveyard to your hand.

Altar of the Wretched // Wretched Bonemass

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Death Tyrant

Menace
Negative Energy Cone — Whenever an attacking creature you control or a blocking creature an opponent controls dies, create a 2/2 black Zombie creature token.
{5}{B}: Return Death Tyrant from your graveyard to the battlefield tapped.

Forsaken Miner

Forsaken Miner can't block.
Whenever you commit a crime, you may pay {B}. If you do, return Forsaken Miner from your graveyard to the battlefield. (Targeting opponents, anything they control, and/or cards in their graveyards is a crime.)

Command Tower

Cult Conscript

Cult Conscript enters tapped.
{1}{B}: Return Cult Conscript from your graveyard to the battlefield. Activate only if a non-Skeleton creature died under your control this turn.

Underground Mortuary

({T}: Add {B} or {G}.)
Underground Mortuary enters tapped.
When Underground Mortuary enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Feed the Swarm

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

Reassembling Skeleton

{1}{B}: Return this card from your graveyard to the battlefield tapped.

Case of the Stashed Skeleton

When this Case enters, create a 2/1 black Skeleton creature token and suspect it. (It has menace and can't block.)
To solve — You control no suspected Skeletons. (If unsolved, solve at the beginning of your end step.)
Solved — {1}{B}, Sacrifice this Case: Search your library for a card, put it into your hand, then shuffle. Activate only as a sorcery.

Dark Ritual

Terror

Destroy target nonartifact, nonblack creature. It can't be regenerated.

Death-Priest of Myrkul

Skeletons, Vampires, and Zombies you control get +1/+1.
At the beginning of your end step, if a creature died this turn, you may pay {1}. If you do, create a 1/1 black Skeleton creature token.

Bone Shards

As an additional cost to cast this spell, sacrifice a creature or discard a card.
Destroy target creature or planeswalker.

Moldervine Reclamation

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

Kjeldoran Dead

When Kjeldoran Dead enters, sacrifice a creature.
{B}: Regenerate Kjeldoran Dead.

Gutterbones

Gutterbones enters tapped.
{1}{B}: Return Gutterbones from your graveyard to your hand. Activate only during your turn and only if an opponent lost life this turn.

Moss-Pit Skeleton

Kicker {3} (You may pay an additional {3} as you cast this spell.)
If Moss-Pit Skeleton was kicked, it enters with three +1/+1 counters on it.
Whenever one or more +1/+1 counters are put on a creature you control, if Moss-Pit Skeleton is in your graveyard, you may put Moss-Pit Skeleton on top of your library.

Carrionette

{2}{B}{B}: Exile Carrionette and target creature unless that creature's controller pays {2}. Activate only if Carrionette is in your graveyard.

Skeletal Swarming

Each Skeleton you control has trample, attacks each combat if able, and gets +X/+0, where X is the number of other Skeletons you control.
At the beginning of your end step, create a tapped 1/1 black Skeleton creature token. If a creature died this turn, create two of those tokens instead.

Skeleton Archer

When this creature enters, it deals 1 damage to any target.

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature of their choice.

Rot Farm Skeleton

Rot Farm Skeleton can't block.
{2}{B}{G}, Mill four cards: Return Rot Farm Skeleton from your graveyard to the battlefield. Activate only as a sorcery.

Buried Alive

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

Rimebound Dead

{S}: Regenerate Rimebound Dead. ({S} can be paid with one mana from a snow source.)

Grim Backwoods

{T}: Add {C}.
{2}{B}{G}, {T}, Sacrifice a creature: Draw a card.

Golgari Signet

Unworthy Dead

Hunted Bonebrute

Menace
When Hunted Bonebrute enters, target opponent creates two 1/1 white Dog creature tokens.
When Hunted Bonebrute dies, each opponent loses 3 life.
Disguise {1}{B}

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Paragon of Open Graves

Other black creatures you control get +1/+1.
{2}{B}, {T}: Another target black creature you control gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)

Augur of Skulls

{1}{B}: Regenerate Augur of Skulls.
Sacrifice Augur of Skulls: Target player discards two cards. Activate only during your upkeep.

Skeleton Crew

Each other creature you control that's a Skeleton or Pirate gets +1/+1.
Whenever one or more creature cards leave your graveyard, create a 2/2 black Skeleton Pirate creature token. (This ability triggers only from the battlefield.)
{5}{B}: Return Skeleton Crew from your graveyard to the battlefield tapped.

Clattering Augur

Clattering Augur can't block.
When Clattering Augur enters, you draw a card and you lose 1 life.
{2}{B}{B}: Return Clattering Augur from your graveyard to your hand.

Village Rites

Persistent Specimen

{2}{B}: Return Persistent Specimen from your graveyard to the battlefield tapped.

Sol Ring

Jet Medallion

Black spells you cast cost {1} less to cast.

Infernal Grasp

Destroy target creature. You lose 2 life.

Corpses of the Lost

Skeletons you control get +1/+0 and have haste.
When Corpses of the Lost 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 Corpses of the Lost to its owner's hand. (You descended if a permanent card was put into your graveyard from anywhere.)

Underworld Sentinel

Whenever Underworld Sentinel attacks, exile target creature card from your graveyard.
When Underworld Sentinel dies, put all cards exiled with it onto the battlefield.

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.)

Vanquisher's Banner

As Vanquisher's Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

Faceless Haven

{T}: Add {C}.
{S}{S}{S}: Faceless Haven becomes a 4/3 creature with vigilance and all creature types until end of turn. It's still a land. ({S} can be paid with one mana from a snow source.)

Culling the Weak

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

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Bone Dragon

Flying
{3}{B}{B}, Exile seven other cards from your graveyard: Return Bone Dragon from your graveyard to the battlefield tapped.

Deadly Brew

Each player sacrifices a creature or planeswalker of their choice. If you sacrificed a permanent this way, you may return another permanent card from your graveyard to your hand.

Cinderbones

Wither (This deals damage to creatures in the form of -1/-1 counters.)
{1}{B}: Regenerate Cinderbones.

Grisly Salvage

Reveal the top five cards of your library. You may put a creature or land card from among them into your hand. Put the rest into your graveyard.