Toxrill, the Corrosive

At the beginning of each end step, put a slime counter on each creature you don't control.
Creatures you don't control get -1/-1 for each slime counter on them.
Whenever a creature you don't control with a slime counter on it dies, create a 1/1 black Slug creature token.
{U}{B}, Sacrifice a Slug: Draw a card.

Tainted Isle

{T}: Add {C}.
{T}: Add {U} or {B}. Activate only if you control a Swamp.

Gloomlake Verge

{T}: Add {U}.
{T}: Add {B}. Activate only if you control an Island or a Swamp.

Yahenni, Undying Partisan

Haste
Whenever a creature an opponent controls dies, put a +1/+1 counter on Yahenni.
Sacrifice another creature: Yahenni gains indestructible until end of turn.

Command Tower

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

Dark Ritual

Curse of the Swine

Exile X target creatures. For each creature exiled this way, its controller creates a 2/2 green Boar creature token.

Maha, Its Feathers Night

Flying, trample
Ward—Discard a card.
Creatures your opponents control have base toughness 1.

Slaughter Specialist

When this creature enters, each opponent creates a 1/1 white Human creature token.
Whenever a creature an opponent controls dies, put a +1/+1 counter on this creature.

Morphic Pool

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

No Mercy

Whenever a creature deals damage to you, destroy it.

Fleshbag Marauder

When this creature enters, each player sacrifices a creature of their choice.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Thought Vessel

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

Sephiroth's Intervention

Destroy target creature. You gain 2 life.

Sephiroth, One-Winged Angel

Flying
Super Nova — As this creature transforms into Sephiroth, One-Winged Angel, you get an emblem with "Whenever a creature dies, target opponent loses 1 life and you gain 1 life."
Whenever Sephiroth attacks, you may sacrifice any number of other creatures. If you do, draw that many cards.

Sephiroth, Fabled SOLDIER

Whenever Sephiroth enters or attacks, you may sacrifice another creature. If you do, draw a card.
Whenever another creature dies, target opponent loses 1 life and you gain 1 life. If this is the fourth time this ability has resolved this turn, transform Sephiroth.

Sephiroth, Fabled SOLDIER // Sephiroth, One-Winged Angel

Sephiroth, Planet's Heir

Vigilance (Attacking doesn't cause this creature to tap.)
When Sephiroth enters, creatures your opponents control get -2/-2 until end of turn.
Whenever a creature an opponent controls dies, put a +1/+1 counter on Sephiroth.

Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Galian Beast

Trample, lifelink
When Galian Beast dies, return it to the battlefield tapped (front face up).

Vincent Valentine

Whenever a creature an opponent controls dies, put a number of +1/+1 counters on Vincent Valentine equal to that creature's power.
Whenever Vincent Valentine attacks, you may transform it.

Vincent Valentine // Galian Beast

Essence Flux

Exile target creature you control, then return that card to the battlefield under its owner's control. If it's a Spirit, put a +1/+1 counter on it.

Irenicus's Vile Duplication

Create a token that's a copy of target creature you control, except the token has flying and it isn't legendary.

Deadly Embrace

Destroy target creature an opponent controls. Then draw a card for each creature that died this turn.

Watery Grave

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

Resentful Revelation

Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.
Flashback {6}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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.

Displacer Kitten

Avoidance — Whenever you cast a noncreature spell, exile up to one target nonland permanent you control, then return that card to the battlefield under its owner's control.

Zodiark, Umbral God

Indestructible
When Zodiark enters, each player sacrifices half the non-God creatures they control of their choice, rounded down.
Whenever a player sacrifices another creature, put a +1/+1 counter on Zodiark.

Blade of Selves

Equipped creature has myriad. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Equip {4}

Sol Ring

Arcane Signet

Overkill

Target creature gets -0/-9999 until end of turn.

Zulaport Cutthroat

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

Massacre Girl

Menace
When Massacre Girl enters, each other creature gets -1/-1 until end of turn. Whenever a creature dies this turn, each creature other than Massacre Girl gets -1/-1 until end of turn.

Underground River

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

Mandate of Abaddon

Choose target creature you control. Destroy all creatures with power less than that creature's power.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Drowned Catacomb

This land enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Massacre Girl, Known Killer

Menace
Creatures you control have wither. (They deal damage to creatures in the form of -1/-1 counters.)
Whenever a creature an opponent controls dies, if its toughness was less than 1, draw a card.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Genesis Chamber

Whenever a nontoken creature enters, if this artifact is untapped, that creature's controller creates a 1/1 colorless Myr artifact creature token.

Toxic Deluge

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

Swamp

Blight Grenade

Destroy target creature.
All creatures get -3/-3 until end of turn.

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

The Masamune

As long as equipped creature is attacking, it has first strike and must be blocked if able.
Equipped creature has "If a creature dying causes a triggered ability of this creature or an emblem you own to trigger, that ability triggers an additional time."
Equip {2}

Sheoldred, Whispering One

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
At the beginning of your upkeep, return target creature card from your graveyard to the battlefield.
At the beginning of each opponent's upkeep, that player sacrifices a creature of their choice.

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Deadeye Navigator

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Deadeye Navigator is paired with another creature, each of those creatures has "{1}{U}: Exile this creature, then return it to the battlefield under your control."

Helm of the Host

At the beginning of combat on your turn, create a token that's a copy of equipped creature, except the token isn't legendary. That token gains haste.
Equip {5}

Terramorphic Expanse

Thassa, Deep-Dwelling

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of your end step, exile up to one other target creature you control, then return that card to the battlefield under your control.
{3}{U}: Tap another target creature.

Black Market

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

Shipwreck Marsh

This land enters tapped unless you control two or more other lands.
{T}: Add {U} or {B}.

The Meathook Massacre

When The Meathook Massacre enters, each creature gets -X/-X until end of turn.
Whenever a creature you control dies, each opponent loses 1 life.
Whenever a creature an opponent controls dies, you gain 1 life.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Conjurer's Closet

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

Planar Incision

Exile target artifact or creature, then return it to the battlefield under its owner's control with a +1/+1 counter on it.

Gray Merchant of Asphodel

When this creature 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.)

Baleful Strix

Flying, deathtouch
When this creature enters, draw a card.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Hunted Phantasm

This creature can't be blocked.
When this creature enters, target opponent creates five 1/1 red Goblin creature tokens.

Victimize

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

Accursed Marauder

When this creature enters, each player sacrifices a nontoken creature of their choice.

In Garruk's Wake

Destroy all creatures you don't control and all planeswalkers you don't control.

Blood Artist

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

Dictate of Erebos

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

Inexorable Tide

Whenever you cast a spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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 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.)

Sunken Hollow

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

Flatline

Creatures your opponents control have base power and toughness 0/1 until end of turn.

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Counterspell

Polymorphist's Jest

Until end of turn, each creature target player controls loses all abilities and becomes a blue Frog with base power and toughness 1/1.

Island

Shinryu, Transcendent Rival

Flying
As this creature transforms into Shinryu, choose an opponent.
Burning Chains — When the chosen player loses the game, you win the game.

Zenos yae Galvus

My First Friend — When Zenos yae Galvus enters, choose a creature an opponent controls. Until end of turn, creatures other than Zenos yae Galvus and the chosen creature get -2/-2.
When the chosen creature leaves the battlefield, transform Zenos yae Galvus.

Zenos yae Galvus // Shinryu, Transcendent Rival

Shizo, Death's Storehouse

{T}: Add {B}.
{B}, {T}: Target legendary creature gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)

Plaguecrafter

When this creature enters, each player sacrifices a creature or planeswalker of their choice. Each player who can't discards a card.