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.

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.)

Deathreap Ritual

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

Reassembling Skeleton

{1}{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.

Realmwalker

Changeling (This card is every creature type.)
As Realmwalker enters, choose a creature type.
You may look at the top card of your library any time.
You may cast creature spells of the chosen type from the top of your library.

Masked Vandal

Changeling (This card is every creature type.)
When Masked Vandal enters, you may exile a creature card from your graveyard. If you do, exile target artifact or enchantment an opponent controls.

Carrionette

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

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.)

Bad Moon

Skeletal Changeling

Changeling (This card is every creature type.)
{1}{B}: Regenerate Skeletal Changeling.

Bone Dragon

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

Hell's Caretaker

{T}, Sacrifice a creature: Return target creature card from your graveyard to the battlefield. Activate only during your upkeep.

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.

Old Stickfingers

When you cast this spell, reveal cards from the top of your library until you reveal X creature cards. Put all creature cards revealed this way into your graveyard, then put the rest on the bottom of your library in a random order.
Old Stickfingers's power and toughness are each equal to the number of creature cards in your graveyard.

Desecrated Tomb

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

Skullclamp

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

Gleancrawler

({B/G} can be paid with either {B} or {G}.)
Trample
At the beginning of your end step, return to your hand all creature cards in your graveyard that were put there from the battlefield this turn.

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.

Tenacious Dead

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

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.

Sanitarium Skeleton

{2}{B}: Return Sanitarium Skeleton from your graveyard to your hand.

Concordant Crossroads

Drudge Spell

{B}, Exile two creature cards from your graveyard: Create a 1/1 black Skeleton creature token. It has "{B}: Regenerate this creature."
When Drudge Spell leaves the battlefield, destroy all Skeleton tokens. They can't be regenerated.

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.)

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.

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.

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.

Persistent Specimen

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