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.

Hunted Bonebrute

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

Clattering Augur

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

Blasphemous Edict

You may pay {B} rather than pay this spell's mana cost if there are thirteen or more creatures on the battlefield.
Each player sacrifices thirteen creatures of their choice.

Golgari Grave-Troll

This creature enters with a +1/+1 counter on it for each creature card in your graveyard.
{1}, Remove a +1/+1 counter from this creature: Regenerate this creature.
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.)

Dread Osseosaur

Menace
Whenever this creature enters or attacks, you may mill two cards. (You may put the top two cards of your library into your graveyard.)

Visage of Dread

When this artifact enters, target opponent reveals their hand. You choose an artifact or creature card from it. That player discards that card.
Craft with two creatures {5}{B} ({5}{B}, Exile this artifact, Exile the two from among creatures you control and/or creature cards in your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

Visage of Dread // Dread Osseosaur

Bone Shards

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

Skeletonize

Skeletonize deals 3 damage to target creature. When a creature dealt damage this way dies this turn, create a 1/1 black Skeleton creature token with "{B}: Regenerate this token."

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.

Forsaken Miner

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

Deathreap Ritual

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

Tenacious Dead

When this creature dies, you may pay {1}{B}. If you do, return it to the battlefield tapped under its owner's control.

Putrefy

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

Ozox, the Clattering King

Ozox can't block.
When Ozox dies, create Jumblebones, a legendary 2/1 black Skeleton creature token with "Jumblebones can't block" and "When Jumblebones leaves the battlefield, return target card named Ozox, the Clattering King from your graveyard to your hand."

Champion of Stray Souls

{3}{B}{B}, {T}, Sacrifice X other creatures: Return X target creature cards from your graveyard to the battlefield.
{5}{B}{B}: Put this card from your graveyard on top of your library.

Savage Lands

This land enters tapped.
{T}: Add {B}, {R}, or {G}.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

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.)

Victimize

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

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.)

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Grave Pact

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

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.)

Cinder Glade

({T}: Add {R} or {G}.)
This land enters tapped unless you control two or more basic lands.

Blood Crypt

({T}: Add {B} or {R}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Terminate

Destroy target creature. It can't be regenerated.

Bone Harvest

Put any number of target creature cards from your graveyard on top of your library.
Draw a card at the beginning of the next turn's upkeep.

Ghastly Death Tyrant

When this creature 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.

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 this card from your graveyard to the battlefield tapped.

Moldervine Reclamation

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

Village Rites

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

Command Tower

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

Blood for Bones

As an additional cost to cast this spell, sacrifice a creature.
Return a creature card from your graveyard to the battlefield, then return another creature card from your graveyard to your hand.

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 this creature, put a creature card exiled with this creature 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.

Vanquisher's Banner

As this artifact 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.

Woodland Cemetery

This land enters tapped unless you control a Swamp or a Forest.
{T}: Add {B} or {G}.

Corrupted Conviction

Bedevil

Destroy target artifact, creature, or planeswalker.

Desecrated Tomb

Whenever one or more creature cards leave your graveyard, create a 1/1 black Bat creature token with flying.

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.)

Smoldering Marsh

({T}: Add {B} or {R}.)
This land enters tapped unless you control two or more basic lands.

Skeletal Vampire

Flying
When this creature 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 this creature.

Persistent Specimen

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

Lightning Skelemental

Trample, haste
Whenever this creature deals combat damage to a player, that player discards two cards.
At the beginning of the end step, sacrifice this creature.

Sanitarium Skeleton

{2}{B}: Return this card from your graveyard to your hand.

Accursed Duneyard

{T}: Add {C}.
{2}, {T}: Regenerate target Shade, Skeleton, Specter, Spirit, Vampire, Wraith, or Zombie. (The next time it would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

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 this card from your graveyard to the battlefield tapped.

Reliquary Tower

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

Bladewing, Deathless Tyrant

Flying, haste
Whenever Bladewing deals combat damage to a player or planeswalker, for each creature card in your graveyard, create a 2/2 black Zombie Knight creature token with menace.

Mountain

Stomping Ground

({T}: Add {R} or {G}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Riveteers Overlook

When this land enters, sacrifice it. When you do, search your library for a basic Swamp, Mountain, or Forest card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

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.

Undergrowth Stadium

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

Dimir House Guard

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Sacrifice a creature: Regenerate this creature.
Transmute {1}{B}{B} ({1}{B}{B}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Overgrown Tomb

({T}: Add {B} or {G}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Kodama's Reach

Unclaimed Territory

As this land 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.

Swamp

Gutterbones

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

Cult Conscript

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

Sek'Kuar, Deathkeeper

Whenever another nontoken creature you control dies, create a 3/1 black and red Graveborn creature token with haste.

Bojuka Bog

This land enters tapped.
When this land enters, exile target player's graveyard.
{T}: Add {B}.

Bone Splinters

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

Forest

Drudge Skeletons

{B}: Regenerate this creature. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Carnage Gladiator

Whenever a creature blocks, that creature's controller loses 1 life.
{1}{B}{R}: Regenerate this creature.

Flameskull

Flying
This creature can't block.
Rejuvenation — When this creature dies, exile it. If you do, exile the top card of your library. Until the end of your next turn, you may play one of those cards. (If you cast Flameskull this way, you can't play the other card, and vice versa.)

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Wretched Bonemass

Wretched Bonemass's power and toughness are each equal to the total power of the exiled cards used to craft it.
This creature 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 this artifact 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 this card from your graveyard to your hand.

Altar of the Wretched // Wretched Bonemass

Gut, True Soul Zealot

Whenever you attack, you may sacrifice another creature or an artifact. If you do, create a 4/1 black Skeleton creature token with menace that's tapped and attacking. (It can't be blocked except by two or more creatures.)
Choose a Background (You can have a Background as a second commander.)

Ziatora's Proving Ground

({T}: Add {B}, {R}, or {G}.)
This land enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Dragonskull Summit

This land enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Underworld Sentinel

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

Sol Ring

Rot Farm Skeleton

This creature can't block.
{2}{B}{G}, Mill four cards: Return this card from your graveyard to the battlefield. Activate only as a sorcery.

Spawning Pool

This land enters tapped.
{T}: Add {B}.
{1}{B}: This land 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.)

Shared Animosity

Whenever a creature you control attacks, it gets +1/+0 until end of turn for each other attacking creature that shares a creature type with it.

Riveteers Ascendancy

Whenever you sacrifice a creature, you may return target creature card with lesser mana value from your graveyard to the battlefield tapped. Do this only once each turn.

Arcane Signet

Twisted Landscape

{T}: Add {C}.
{T}, Sacrifice this land: Search your library for a basic Swamp, Mountain, or Forest card, put it onto the battlefield tapped, then shuffle.
Cycling {B}{R}{G} ({B}{R}{G}, Discard this card: Draw a card.)

Llanowar Wastes

{T}: Add {C}.
{T}: Add {B} or {G}. This land deals 1 damage to you.

Moss-Pit Skeleton

Kicker {3} (You may pay an additional {3} as you cast this spell.)
If this creature 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 this card is in your graveyard, you may put this card on top of your library.

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 token: Add one mana of any color.")

Insidious Roots

Creature tokens you control have "{T}: Add one mana of any color."
Whenever one or more creature cards leave your graveyard, create a 0/1 green Plant creature token, then put a +1/+1 counter on each Plant you control.

Convergence of Dominion

Dynastic Command Node — As long as you control your commander, activated abilities of cards in your graveyard cost {2} less to activate. This effect can't reduce the mana in that ability's activation cost to less than one mana.
Translocation Protocols — {3}, {T}: Mill three cards.

Bone Offering

Create a tapped 4/1 black Skeleton creature token with menace. (Then exile this card. You may cast the artifact later from exile.)

Altar of Bhaal

{2}{B}, {T}, Exile a creature you control: Return target creature card from your graveyard to the battlefield. Activate only as a sorcery.