Malcator's Watcher

Flying, vigilance
When Malcator's Watcher dies, draw a card.

Dimir Aqueduct

Dimir Aqueduct enters tapped.
When Dimir Aqueduct enters, return a land you control to its owner's hand.
{T}: Add {U}{B}.

Mephitic Vapors

All creatures get -1/-1 until end of turn.
Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Nocturnal Feeder

Flying
When Nocturnal Feeder dies, each opponent loses 2 life and you gain 2 life.

Atrocious Experiment

Target player mills two cards, draws two cards, and loses 2 life. (To mill a card, a player puts the top card of their library into their graveyard.)

Scream Puff

Deathtouch
Whenever Scream Puff deals combat damage to a player, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Dimir Signet

Contaminated Aquifer

({T}: Add {U} or {B}.)
Contaminated Aquifer enters tapped.

Demon's Disciple

When Demon's Disciple enters, each player sacrifices a creature or planeswalker of their choice.

Mire Triton

Deathtouch
When Mire Triton enters, mill two cards and you gain 2 life. (To mill a card, put the top card of your library into your graveyard.)

Probe

Kicker {1}{B} (You may pay an additional {1}{B} as you cast this spell.)
Draw three cards, then discard two cards. If this spell was kicked, target player discards two cards.

Phyrexian Rager

When Phyrexian Rager enters, you draw a card and you lose 1 life.

Underdark Explorer

Menace (This creature can't be blocked except by two or more creatures.)
When Underdark Explorer enters, you take the initiative.

Dark Bargain

Look at the top three cards of your library. Put two of them into your hand and the other into your graveyard. Dark Bargain deals 2 damage to you.

Drown in Sorrow

All creatures get -2/-2 until end of turn. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Wailing Ghoul

When Wailing Ghoul enters, mill two cards. (Put the top two cards of your library into your graveyard.)

Mental Note

Serrated Scorpion

When Serrated Scorpion dies, it deals 2 damage to each opponent and you gain 2 life.

Waterfront District

Waterfront District enters tapped.
{T}: Add {U} or {B}.
{2}{U}{B}, {T}, Sacrifice Waterfront District: Draw a card.

Ithilien Kingfisher

Flying
When Ithilien Kingfisher dies, draw a card.

Snooping Newsie

When Snooping Newsie enters, mill two cards. (Put the top two cards of your library into your graveyard.)
As long as there are five or more mana values among cards in your graveyard, Snooping Newsie gets +1/+1 and has lifelink.

Maalfeld Twins

When this creature dies, create two 2/2 black Zombie creature tokens.

Emergency Weld

Return target artifact or creature card from your graveyard to your hand. Create a 1/1 colorless Soldier artifact creature token.

Island

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Cryptic Serpent

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.

Diregraf Scavenger

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When Diregraf Scavenger enters, exile up to one target card from a graveyard. If a creature card was exiled this way, each opponent loses 2 life and you gain 2 life.

Go for the Throat

Phantasmal Dreadmaw

Trample
When Phantasmal Dreadmaw becomes the target of a spell or ability, sacrifice it.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Araumi of the Dead Tide

{T}, Exile cards from your graveyard equal to the number of opponents you have: Target creature card in your graveyard gains encore until end of turn. The encore cost is equal to its mana cost. (Exile the creature card and pay its mana cost: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

Chain Devil

Animate Chains — When Chain Devil enters, each player sacrifices a nontoken creature of their choice.

Tolarian Winds

Discard all the cards in your hand, then draw that many cards.

Snarling Gorehound

Menace
Whenever another creature you control with power 2 or less enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Gloomfang Mauler

Swampcycling {2} ({2}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)
Backup 2 (When this creature enters, put two +1/+1 counters on target creature. If that's another creature, it gains the following ability until end of turn.)
Menace

Deep Analysis

Target player draws two cards.
Flashback—{1}{U}, Pay 3 life. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Evolving Wilds

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

Flitting Guerrilla

Flying
When Flitting Guerrilla dies, each player mills two cards. Then you may exile Flitting Guerrilla. When you do, put target creature or battle card from your graveyard on top of your library. (To mill two cards, a player puts the top two cards of their library into their graveyard.)

Altar's Reap

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

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.)

Ice Tunnel

({T}: Add {U} or {B}.)
Ice Tunnel enters tapped.

Alchemist's Apprentice

Sacrifice Alchemist's Apprentice: Draw a card.

Rot-Tide Gargantua

Exploit (When this creature enters, you may sacrifice a creature.)
When Rot-Tide Gargantua exploits a creature, each opponent sacrifices a creature of their choice.

Swamp

Archaeomancer

When Archaeomancer enters, return target instant or sorcery card from your graveyard to your hand.

Mintstrosity

When Mintstrosity dies, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Fleshbag Marauder

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

Unseal the Necropolis

Each player mills three cards. Then you return up to two creature cards from your graveyard to your hand. (To mill three cards, a player puts the top three cards of their library into their graveyard.)

Exhume

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

Dunland Crebain

Flying
When Dunland Crebain enters, amass Orcs 2. (Put two +1/+1 counters on an Army you control. It's also an Orc. If you don't control an Army, create a 0/0 black Orc Army creature token first.)

Terramorphic Expanse

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

Corpse Churn

Mill three cards, then you may return a creature card from your graveyard to your hand. (To mill three cards, put the top three cards of your library into your graveyard.)

Gluttonous Guest

When Gluttonous Guest enters, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")
Whenever you sacrifice a Blood token, you gain 1 life.

Shepherd of Rot

{T}: Each player loses 1 life for each Zombie on the battlefield.

Secrets of the Key

Investigate. If this spell was cast from a graveyard, investigate twice instead. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Flashback {3}{U}

Arcane Signet

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

Cast Down

Candy Grapple

Bargain (You may sacrifice an artifact, enchantment, or token as you cast this spell.)
Target creature gets -3/-3 until end of turn. If this spell was bargained, that creature gets -5/-5 until end of turn instead.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Fellwar Stone

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

Dreamscape Artist

{2}{U}, {T}, Discard a card, Sacrifice a land: Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Primordial Gnawer

When Primordial Gnawer dies, discover 3. (Exile cards from the top of your library until you exile a nonland card with mana value 3 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Crow of Dark Tidings

Flying
When this creature enters or dies, mill two cards. (Put the top two cards of your library into your graveyard.)

Deranged Assistant

{T}, Mill a card: Add {C}. (To mill a card, put the top card of your library into your graveyard.)

Foul Watcher

Flying
When Foul Watcher enters, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
Delirium — Foul Watcher gets +1/+0 as long as there are four or more card types among cards in your graveyard.

Murder

Guildsworn Prowler

Deathtouch
When Guildsworn Prowler dies, if it wasn't blocking, draw a card.

Vivisurgeon's Insight

Draw three cards. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

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.)

Lotleth Giant

Undergrowth — When Lotleth Giant enters, it deals 1 damage to target opponent for each creature card in your graveyard.

Combat Courier

{2}, Sacrifice Combat Courier: Draw a card.
Unearth {U} ({U}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)