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.

Sakura-Tribe Elder

Sacrifice Sakura-Tribe Elder: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Exquisite Blood

Whenever an opponent loses life, you gain that much life.

Bontu's Monument

Black creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, each opponent loses 1 life and you gain 1 life.

Pristine Talisman

Hunt for Specimens

Create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."
Learn. (You may reveal a Lesson card you own from outside the game and put it into your hand, or discard a card to draw a card.)

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Llanowar Wastes

{T}: Add {C}.
{T}: Add {B} or {G}. Llanowar Wastes deals 1 damage to you.

Epicure of Blood

Whenever you gain life, each opponent loses 1 life.

Acidic Slime

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When Acidic Slime enters, destroy target artifact, enchantment, or land.

Silversmote Ghoul

At the beginning of your end step, if you gained 3 or more life this turn, return Silversmote Ghoul from your graveyard to the battlefield tapped.
{1}{B}, Sacrifice Silversmote Ghoul: Draw a card.

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Dark Ritual

Managorger Hydra

Trample
Whenever a player casts a spell, put a +1/+1 counter on Managorger Hydra.

Essence Warden

Whenever another creature enters, you gain 1 life.

Dictate of Erebos

Flash
Whenever a creature you control dies, each opponent sacrifices a creature of their choice.

Grim Haruspex

Morph {B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
Whenever another nontoken creature you control dies, draw a card.

Forest

Feign Death

Until end of turn, target creature gains "When this creature dies, return it to the battlefield tapped under its owner's control with a +1/+1 counter on it."

Carrion Feeder

Carrion Feeder can't block.
Sacrifice a creature: Put a +1/+1 counter on Carrion Feeder.

Beledros Witherbloom

Flying
At the beginning of each upkeep, create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."
Pay 10 life: Untap all lands you control. Activate only once each turn.

Revenge of Ravens

Whenever a creature attacks you or a planeswalker you control, that creature's controller loses 1 life and you gain 1 life.

Doom Blade

Farseek

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

Woodland Cemetery

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

High Market

{T}: Add {C}.
{T}, Sacrifice a creature: You gain 1 life.

Relic Vial

{2}, {T}, Sacrifice a creature: Draw a card.
As long as you control a Cleric, Relic Vial has "Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life."

Lampad of Death's Vigil

{1}, Sacrifice a creature: Each opponent loses 1 life and you gain 1 life.

Diabolic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Zulaport Cutthroat

Whenever Zulaport Cutthroat or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Llanowar Elves

Blood Researcher

Menace (This creature can't be blocked except by two or more creatures.)
Whenever you gain life, put a +1/+1 counter on Blood Researcher.

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.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Dig Up

Cleave {1}{B}{B}{G} (You may cast this spell for its cleave cost. If you do, remove the words in square brackets.)
Search your library for a [basic land] card, [reveal it,] put it into your hand, then shuffle.

Lisette, Dean of the Root

Whenever you gain life, you may pay {1}. If you do, put a +1/+1 counter on each creature you control and those creatures gain trample until end of turn.

Valentin, Dean of the Vein

Menace, lifelink
If a nontoken creature an opponent controls would die, exile it instead. When you do, you may pay {2}. If you do, create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."

Valentin, Dean of the Vein // Lisette, Dean of the Root

Jungle Hollow

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {B} or {G}.

Butcher of Malakir

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

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.)

Druid Class

(Gain the next level as a sorcery to add its ability.)
Landfall — Whenever a land you control enters, you gain 1 life.
{2}{G}: Level 2
You may play an additional land on each of your turns.
{4}{G}: Level 3
When this Class becomes level 3, target land you control becomes a creature with haste and "This creature's power and toughness are each equal to the number of lands you control." It's still a land.

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Sign in Blood

Target player draws two cards and loses 2 life.

Bloodthirsty Aerialist

Flying
Whenever you gain life, put a +1/+1 counter on Bloodthirsty Aerialist.

Massacre Wurm

When this creature enters, creatures your opponents control get -2/-2 until end of turn.
Whenever a creature an opponent controls dies, that player loses 2 life.

Disciple of Griselbrand

{1}, Sacrifice a creature: You gain life equal to the sacrificed creature's toughness.

Putrefy

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

Reassembling Skeleton

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

Greed

Tablet of the Guilds

As Tablet of the Guilds enters, choose two colors.
Whenever you cast a spell, if it's at least one of the chosen colors, you gain 1 life for each of the chosen colors it is.

Skullclamp

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

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.

Deathgreeter

Whenever another creature dies, you may gain 1 life.

Trudge Garden

Whenever you gain life, you may pay {2}. If you do, create a 4/4 green Fungus Beast creature token with trample.

Dina, Soul Steeper

Whenever you gain life, each opponent loses 1 life.
{1}, Sacrifice another creature: Dina, Soul Steeper gets +X/+0 until end of turn, where X is the sacrificed creature's power.

Innocent Blood

Each player sacrifices a creature of their choice.

Smallpox

Each player loses 1 life, discards a card, sacrifices a creature of their choice, then sacrifices a land of their choice.

Marauding Blight-Priest

Callous Bloodmage

When Callous Bloodmage enters, choose one —
• Create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."
• You draw a card and you lose 1 life.
• Exile target player's graveyard.

Blight Mound

Attacking Pests you control get +1/+0 and have menace.
Whenever a nontoken creature you control dies, create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."

Naturalize

Black Market

Whenever a creature dies, put a charge counter on Black Market.
At the beginning of your first main phase, add {B} for each charge counter on Black Market.

Krosan Grip

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Destroy target artifact or enchantment.

Shessra, Death's Whisper

Bewitching Whispers — When Shessra, Death's Whisper enters, target creature blocks this turn if able.
Whispers of the Grave — At the beginning of your end step, if a creature died this turn, you may pay 2 life. If you do, draw a card.

Prosperous Innkeeper

When Prosperous Innkeeper enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Whenever another creature you control enters, you gain 1 life.

Chain of Smog

Target player discards two cards. That player may copy this spell and may choose a new target for that copy.

Blood Bairn

Sacrifice another creature: Blood Bairn gets +2/+2 until end of turn.

Night Market Lookout

Whenever Night Market Lookout becomes tapped, each opponent loses 1 life and you gain 1 life.

Swamp

Moldervine Reclamation

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

Sol Ring

Witherbloom Apprentice

Magecraft — Whenever you cast or copy an instant or sorcery spell, each opponent loses 1 life and you gain 1 life.

Rampant Growth

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

Profane Memento

Whenever a creature card is put into an opponent's graveyard from anywhere, you gain 1 life.

Fyndhorn Elves

Vampiric Rites

{1}{B}, Sacrifice a creature: You gain 1 life and draw a card.

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.

Falkenrath Noble

Flying
Whenever Falkenrath Noble or another creature dies, target player loses 1 life and you gain 1 life.