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, the Grim 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.)

Rampant Growth

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

Jarad, Golgari Lich Lord

Jarad, Golgari Lich Lord gets +1/+1 for each creature card in your graveyard.
{1}{B}{G}, Sacrifice another creature: Each opponent loses life equal to the sacrificed creature's power.
Sacrifice a Swamp and a Forest: Return Jarad from your graveyard to your hand.

Souls of the Lost

As an additional cost to cast this spell, discard a card or sacrifice a permanent.
Fathomless descent — Souls of the Lost's power is equal to the number of permanent cards in your graveyard and its toughness is equal to that number plus 1.

Giant Adephage

Trample
Whenever Giant Adephage deals combat damage to a player, create a token that's a copy of Giant Adephage.

Ever After

Return up to two target creature cards from your graveyard to the battlefield. Each of those creatures is a black Zombie in addition to its other colors and types. Put Ever After on the bottom of its owner's library.

Vigor Mortis

Return target creature card from your graveyard to the battlefield. If {G} was spent to cast this spell, that creature enters with an additional +1/+1 counter on it.

Harrow

As an additional cost to cast this spell, sacrifice a land.
Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Terastodon

When Terastodon enters, you may destroy up to three target noncreature permanents. For each permanent put into a graveyard this way, its controller creates a 3/3 green Elephant creature token.

Old Rutstein

When Old Rutstein enters and at the beginning of your upkeep, mill a card. If a land card is milled this way, create a Treasure token. If a creature card is milled this way, create a 1/1 green Insect creature token. If a noncreature, nonland card is milled this way, create a Blood token.

Bringer of the Last Gift

Flying
When Bringer of the Last Gift enters, if you cast it, each player sacrifices all other creatures they control. Then each player returns all creature cards from their graveyard that weren't put there this way to the battlefield.

Victimize

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

The Core

(Transforms from Matzalantli.)
Fathomless descent — {T}: Add X mana of any one color, where X is the number of permanent cards in your graveyard.

Matzalantli, the Great Door

{T}: Draw a card, then discard a card.
{4}, {T}: Transform Matzalantli, the Great Door. Activate only if there are four or more permanent types among cards in your graveyard. (Artifact, battle, creature, enchantment, land, and planeswalker are permanent types.)

Matzalantli, the Great Door // The Core

Diregraf Rebirth

This spell costs {1} less to cast for each creature that died this turn.
Return target creature card from your graveyard to the battlefield.
Flashback {5}{B}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Exhume

Each player puts a creature card from their graveyard onto the battlefield.

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.

Butcher of Malakir

Flying
Whenever Butcher of Malakir or another creature you control dies, each opponent sacrifices a creature of their choice.

Izoni, Thousand-Eyed

Undergrowth — When Izoni, Thousand-Eyed enters, create a 1/1 black and green Insect creature token for each creature card in your graveyard.
{B}{G}, Sacrifice another creature: You gain 1 life and draw a card.

Putrefy

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

Moldgraf Monstrosity

Trample
When Moldgraf Monstrosity dies, exile it, then return two creature cards at random from your graveyard to the battlefield.

Squirming Emergence

Fathomless descent — Return to the battlefield target nonland permanent card in your graveyard with mana value less than or equal to the number of permanent cards in your graveyard.

Animate Dead

Enchant creature card in a graveyard
When Animate Dead enters, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets -1/-0.

Terror Tide

Fathomless descent — All creatures get -X/-X until end of turn, where X is the number of permanent cards in your graveyard.

Overwhelming Remorse

This spell costs {1} less to cast for each creature card in your graveyard.
Exile target creature or planeswalker.

Necropolis Regent

Flying
Whenever a creature you control deals combat damage to a player, put that many +1/+1 counters on it.

Necrotic Ooze

As long as Necrotic Ooze is on the battlefield, it has all activated abilities of all creature cards in all graveyards.

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.

Dawnglade Regent

When Dawnglade Regent enters, you become the monarch.
As long as you're the monarch, permanents you control have hexproof.

Overseer of the Damned

Flying
When Overseer of the Damned enters, you may destroy target creature.
Whenever a nontoken creature an opponent controls dies, create a tapped 2/2 black Zombie creature token.

Rise of the Witch-king

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

Deathbloom Ritualist

{T}: Add X mana of any one color, where X is the number of creature cards in your graveyard.

Dread Return

Return target creature card from your graveyard to the battlefield.
Flashback—Sacrifice three creatures. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Deathsprout

Destroy target creature. Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Whisper, Blood Liturgist

{T}, Sacrifice two creatures: Return target creature card from your graveyard to the battlefield.