Corrupted Conviction

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

Voracious Vermin

When Voracious Vermin enters the battlefield, create a 1/1 black Rat creature token with "This creature can't block."
Whenever another creature you control dies, put a +1/+1 counter on Voracious Vermin.

Swarm of Rats

Swarm of Rats's power is equal to the number of Rats you control.

Commander's Sphere

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

Magus of the Coffers

{2}, {T}: Add {B} for each Swamp you control.

Gauntlet of Power

As Gauntlet of Power enters the battlefield, choose a color.
Creatures of the chosen color get +1/+1.
Whenever a basic land is tapped for mana of the chosen color, its controller adds an additional one mana of that color.

Hall of Triumph

As Hall of Triumph enters the battlefield, choose a color.
Creatures you control of the chosen color get +1/+1.

Assassin's Ink

This spell costs {1} less to cast if you control an artifact and {1} less to cast if you control an enchantment.
Destroy target creature or planeswalker.

Sigil of Myrkul

At the beginning of combat on your turn, mill a card. When you do, if there are four or more creature cards in your graveyard, put a +1/+1 counter on target creature you control and it gains deathtouch until end of turn. (To mill a card, put the top card of your library into your graveyard.)

Grixis Panorama

{T}: Add {C}.
{1}, {T}, Sacrifice Grixis Panorama: Search your library for a basic Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Ruin Rat

Deathtouch
When Ruin Rat dies, exile target card from an opponent's graveyard.

Ghastly Gloomhunter

Kicker {3}{B} (You may pay an additional {3}{B} as you cast this spell.)
Flying, lifelink
If Ghastly Gloomhunter was kicked, it enters the battlefield with two +1/+1 counters on it.

Rats of Rath

{B}: Destroy target artifact, creature, or land you control.

Kelinore Bat

Vampire Bats

Flying (This creature can't be blocked except by creatures with flying or reach.)
{B}: Vampire Bats gets +1/+0 until end of turn. Activate no more than twice each turn.

Strange Augmentation

Enchant creature
Enchanted creature gets +1/+1.
Delirium — Enchanted creature gets an additional +2/+2 as long as there are four or more card types among cards in your graveyard.

Deep-Cavern Bat

Flying, lifelink
When Deep-Cavern Bat enters the battlefield, look at target opponent's hand. You may exile a nonland card from it until Deep-Cavern Bat leaves the battlefield.

Crypt Rats

{X}: Crypt Rats deals X damage to each creature and each player. Spend only black mana on X.

Sewer Rats

{B}, Pay 1 life: Sewer Rats gets +1/+0 until end of turn. Activate no more than three times each turn.

Battle-Rage Blessing

Target creature gains deathtouch and indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Sol Ring

Disease Carriers

When Disease Carriers dies, target creature gets -2/-2 until end of turn.

Cabal Stronghold

{T}: Add {C}.
{3}, {T}: Add {B} for each basic Swamp you control.

Mirkwood Bats

Flying
Whenever you create or sacrifice a token, each opponent loses 1 life.

Reliquary Tower

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

Malakir Familiar

Flying, deathtouch
Whenever you gain life, Malakir Familiar gets +1/+1 until end of turn.

Stalking Vampire

At the beginning of your upkeep, you may pay {2}{B}{B}. If you do, transform Stalking Vampire.

Screeching Bat

Flying
At the beginning of your upkeep, you may pay {2}{B}{B}. If you do, transform Screeching Bat.

Screeching Bat // Stalking Vampire

Razortooth Rats

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

Unstable Obelisk

{T}: Add {C}.
{7}, {T}, Sacrifice Unstable Obelisk: Destroy target permanent.

In Garruk's Wake

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

Swamp

Sinister Strength

Enchant creature
Enchanted creature gets +3/+1 and is black.

Arcane Signet

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

Bleed Dry

Target creature gets -13/-13 until end of turn. If that creature would die this turn, exile it instead.

Ossuary Rats

When Ossuary Rats enters the battlefield, it deals X damage to target creature or planeswalker an opponent controls, where X is the number of creature cards in your graveyard.

Read the Bones

Scry 2, then draw two cards. You lose 2 life.

Black Sun's Twilight

Up to one target creature gets -X/-X until end of turn. If X is 5 or more, return a creature card with mana value X or less from your graveyard to the battlefield tapped.

Rabid Rats

{T}: Target blocking creature gets -1/-1 until end of turn.

Scavenged Weaponry

Enchant creature
When Scavenged Weaponry enters the battlefield, draw a card.
Enchanted creature gets +1/+1.

Rancid Rats

Skulk (This creature can't be blocked by creatures with greater power.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Endless Scream

Enchant creature
Endless Scream enters the battlefield with X scream counters on it.
Enchanted creature gets +1/+0 for each scream counter on Endless Scream.

Another Chance

You may mill two cards. Then return up to two creature cards from your graveyard to your hand. (To mill two cards, put the top two cards of your library into your graveyard.)

Dark Favor

Enchant creature
When Dark Favor enters the battlefield, you lose 1 life.
Enchanted creature gets +3/+1.

Gloomhunter

Sinuous Vermin

{3}{B}{B}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
As long as Sinuous Vermin is monstrous, it has menace. (It can't be blocked except by two or more creatures.)

Cower in Fear

Creatures your opponents control get -1/-1 until end of turn.

Marrow Bats

Flying
Pay 4 life: Regenerate Marrow Bats.

Caged Sun

As Caged Sun enters the battlefield, choose a color.
Creatures you control of the chosen color get +1/+1.
Whenever a land's ability causes you to add one or more mana of the chosen color, add one additional mana of that color.

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.)

Burglar Rat

When Burglar Rat enters the battlefield, each opponent discards a card.

Stronghold Rats

Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever Stronghold Rats deals combat damage to a player, each player discards a card.

Phyrexian Boon

Enchant creature
Enchanted creature gets +2/+1 as long as it's black. Otherwise, it gets -1/-2.

Gnat Miser

Each opponent's maximum hand size is reduced by one.

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Typhoid Rats

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Wave of Rats

Trample
When Wave of Rats dies, if it dealt combat damage to a player this turn, return it to the battlefield under its owner's control.
Blitz {4}{B} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Bartizan Bats

Flying (This creature can't be blocked except by creatures with flying or reach.)

Lord Skitter, Sewer King

Whenever another Rat enters the battlefield under your control, exile up to one target card from an opponent's graveyard.
At the beginning of combat on your turn, create a 1/1 black Rat creature token with "This creature can't block."

Unholy Indenture

Enchant creature
When enchanted creature dies, return that card to the battlefield under your control with a +1/+1 counter on it.

Piranha Marsh

Piranha Marsh enters the battlefield tapped.
When Piranha Marsh enters the battlefield, target player loses 1 life.
{T}: Add {B}.

Basilica Screecher

Flying
Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)

Spiteful Returned

Bestow {3}{B} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Whenever Spiteful Returned or enchanted creature attacks, defending player loses 2 life.
Enchanted creature gets +1/+1.

Mind Stone

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

Muck Rats

Heraldic Banner

As Heraldic Banner enters the battlefield, choose a color.
Creatures you control of the chosen color get +1/+0.
{T}: Add one mana of the chosen color.

Door of Destinies

As Door of Destinies enters the battlefield, choose a creature type.
Whenever you cast a spell of the chosen type, put a charge counter on Door of Destinies.
Creatures you control of the chosen type get +1/+1 for each charge counter on Door of Destinies.

Ravenous Rats

When Ravenous Rats enters the battlefield, target opponent discards a card.

Courier Bat

Flying
When Courier Bat enters the battlefield, if you gained life this turn, return up to one target creature card from your graveyard to your hand.

Vampiric Embrace

Enchant creature
Enchanted creature gets +2/+2 and has flying.
Whenever a creature dealt damage by enchanted creature this turn dies, put a +1/+1 counter on that creature.

Demonic Embrace

Enchant creature
Enchanted creature gets +3/+1, has flying, and is a Demon in addition to its other types.
You may cast Demonic Embrace from your graveyard by paying 3 life and discarding a card in addition to paying its other costs.

Infected Vermin

{2}{B}: Infected Vermin deals 1 damage to each creature and each player.
Threshold — {3}{B}: Infected Vermin deals 3 damage to each creature and each player. Activate only if seven or more cards are in your graveyard.

Midnight Scavengers

When Midnight Scavengers enters the battlefield, you may return target creature card with mana value 3 or less from your graveyard to your hand.
(Melds with Graf Rats.)

Lord Skitter's Butcher

When Lord Skitter's Butcher enters the battlefield, choose one —
• Create a 1/1 black Rat creature token with "This creature can't block."
• You may sacrifice another creature. If you do, scry 2, then draw a card.
• Creatures you control gain menace until end of turn.

Retreat to Hagra

Landfall — Whenever a land enters the battlefield under your control, choose one —
• Target creature gets +1/+0 and gains deathtouch until end of turn.
• Each opponent loses 1 life and you gain 1 life.

Bloodhunter Bat

Flying
When Bloodhunter Bat enters the battlefield, target player loses 2 life and you gain 2 life.

Sadistic Glee

Enchant creature
Whenever a creature dies, put a +1/+1 counter on enchanted creature.

Evolving Wilds

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

Go for the Throat

Charcoal Diamond

Charcoal Diamond enters the battlefield tapped.
{T}: Add {B}.

Old Flitterfang

Flying
At the beginning of each end step, if a creature died this turn, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
{2}{B}, Sacrifice another creature or artifact: Old Flitterfang gets +2/+2 until end of turn.

Bojuka Bog

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

Pestilence Rats

Pestilence Rats's power is equal to the number of other Rats on the battlefield. (For example, as long as there are two other Rats on the battlefield, Pestilence Rats's power and toughness are 2/3.)

Twisted Embrace

Enchant artifact or creature you control
When Twisted Embrace enters the battlefield, destroy target creature or planeswalker an opponent controls.
As long as enchanted permanent is a creature, it gets +1/+1.

Eternal Thirst

Enchant creature
Enchanted creature has lifelink and "Whenever a creature an opponent controls dies, put a +1/+1 counter on this creature." (Damage dealt by a creature with lifelink also causes its controller to gain that much life.)

Bog Rats

Temple of the False God

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

Gutter Skulk

Onyx Talisman

Whenever a player casts a black spell, you may pay {3}. If you do, untap target permanent.

Gruesome Fate

Each opponent loses 1 life for each creature you control.

Mask of Avacyn

Equipped creature gets +1/+2 and has hexproof. (It can't be the target of spells or abilities your opponents control.)
Equip {3}

Foundry Screecher

Flying
Foundry Screecher gets +1/+0 as long as you control an artifact.

Baleful Eidolon

Bestow {4}{B} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Enchanted creature gets +1/+1 and has deathtouch.

Tangled Colony

Tangled Colony can't block.
When Tangled Colony dies, create X 1/1 black Rat creature tokens with "This creature can't block," where X is the amount of damage dealt to it this turn.

Blight Keeper

Flying
{7}{B}, {T}, Sacrifice Blight Keeper: Target opponent loses 4 life and you gain 4 life.

Champion's Helm

Equipped creature gets +2/+2.
As long as equipped creature is legendary, it has hexproof. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Dark Ritual

Mutilate

All creatures get -1/-1 until end of turn for each Swamp you control.

Twisted Sewer-Witch

When Twisted Sewer-Witch enters the battlefield, create a 1/1 black Rat creature token with "This creature can't block." Then for each Rat you control, create a Wicked Role token attached to that Rat. (If you control another Role on it, put that one into the graveyard. Enchanted creature gets +1/+1. When this Aura is put into a graveyard, each opponent loses 1 life.)

Rotting Rats

When Rotting Rats enters the battlefield, each player discards a card.
Unearth {1}{B} ({1}{B}: 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.)

Aspect of Gorgon

Enchant creature
Enchanted creature gets +1/+3 and has deathtouch. (Any amount of damage it deals to a creature is enough to destroy it.)

Grimclaw Bats

Flying
{B}, Pay 1 life: Grimclaw Bats gets +1/+1 until end of turn.

Nyxborn Eidolon

Bestow {4}{B} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Enchanted creature gets +2/+1.

Demonic Vigor

Enchant creature
Enchanted creature gets +1/+1.
When enchanted creature dies, return that card to its owner's hand.