Staff of the Death Magus

Whenever you cast a black spell or a Swamp enters the battlefield under your control, you gain 1 life.

Molting Snakeskin

Enchant creature
Enchanted creature gets +2/+0 and has "{2}{B}: Regenerate this creature."

Dead Reckoning

You may put target creature card from your graveyard on top of your library. If you do, Dead Reckoning deals damage equal to that card's power to target creature.

Rabid Rats

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

Chittering Rats

When Chittering Rats enters the battlefield, target opponent puts a card from their hand on top of their library.

Crypt Rats

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

Bojuka Bog

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

Pack Rat

Pack Rat's power and toughness are each equal to the number of Rats you control.
{2}{B}, Discard a card: Create a token that's a copy of Pack Rat.

Swamp

Demon's Horn

Whenever a player casts a black spell, you may gain 1 life.

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.)

Victim of Night

Destroy target non-Vampire, non-Werewolf, non-Zombie creature.

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.)

Nezumi Cutthroat

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

Swarm of Rats

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

Nezumi Bone-Reader

{B}, Sacrifice a creature: Target player discards a card. Activate only as a sorcery.

Icon of Ancestry

As Icon of Ancestry enters the battlefield, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{3}, {T}: Look at the top three cards of your library. You may reveal a creature card of the chosen type from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Dirty Wererat

{B}, Discard a card: Regenerate Dirty Wererat.
Threshold — As long as seven or more cards are in your graveyard, Dirty Wererat gets +2/+2 and can't block.

Sorin's Thirst

Sorin's Thirst deals 2 damage to target creature and you gain 2 life.

Cruel Revival

Destroy target non-Zombie creature. It can't be regenerated. Return up to one target Zombie card from your graveyard to your hand.

Graf Rats

At the beginning of combat on your turn, if you both own and control Graf Rats and a creature named Midnight Scavengers, exile them, then meld them into Chittering Host.

Ichor Rats

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
When Ichor Rats enters the battlefield, each player gets a poison counter.

Consume Spirit

Spend only black mana on X.
Consume Spirit deals X damage to any target and you gain X life.

Stronghold Discipline

Each player loses 1 life for each creature they control.

Swallowing Plague

Swallowing Plague deals X damage to target creature and you gain X life.

Unholy Strength

Enchant creature
Enchanted creature gets +2/+1.

Ink-Eyes, Servant of Oni

Ninjutsu {3}{B}{B} ({3}{B}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Ink-Eyes, Servant of Oni deals combat damage to a player, you may put target creature card from that player's graveyard onto the battlefield under your control.
{1}{B}: Regenerate Ink-Eyes.

Terramorphic Expanse

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

Kaya's Ghostform

Enchant creature or planeswalker you control
When enchanted permanent dies or is put into exile, return that card to the battlefield under your control.

Swiftfoot Boots

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

Razortooth Rats

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

Doom Blade

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.

Gnat Miser

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

Nezumi Ronin

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)

Throat Slitter

Ninjutsu {2}{B} ({2}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Throat Slitter deals combat damage to a player, destroy target nonblack creature that player controls.

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
Everflowing Chalice enters the battlefield with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on Everflowing Chalice.

Sorin Markov

+2: Sorin Markov deals 2 damage to any target and you gain 2 life.
−3: Target opponent's life total becomes 10.
−7: You control target player during that player's next turn.

Kuro's Taken

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)
{1}{B}: Regenerate Kuro's Taken.

Disease Carriers

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

Meteorite

When Meteorite enters the battlefield, it deals 2 damage to any target.
{T}: Add one mana of any color.

Locust Miser

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

Disentomb

Return target creature card from your graveyard to your hand.

Coat of Arms

Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Goblin Warriors and a Goblin Shaman are on the battlefield, each gets +2/+2.)

Rats of Rath

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

Bond of Revival

Return target creature card from your graveyard to the battlefield. It gains haste until your next turn.

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.)

Contagion Engine

When Contagion Engine enters the battlefield, put a -1/-1 counter on each creature target player controls.
{4}, {T}: Proliferate twice. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)

Typhoid Rats

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

Rat Colony

Rat Colony gets +1/+0 for each other Rat you control.
A deck can have any number of cards named Rat Colony.

Skeletal Grimace

Enchant creature
Enchanted creature gets +1/+1 and has "{B}: Regenerate this creature."

Bog Rats

Grim Discovery

Choose one or both —
• Return target creature card from your graveyard to your hand.
• Return target land card from your graveyard to your hand.

Okiba-Gang Shinobi

Ninjutsu {3}{B} ({3}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Okiba-Gang Shinobi deals combat damage to a player, that player discards two cards.

Vicious Betrayal

As an additional cost to cast this spell, sacrifice any number of creatures.
Target creature gets +2/+2 until end of turn for each creature sacrificed this way.

Grim Harvest

Return target creature card from your graveyard to your hand.
Recover {2}{B} (When a creature is put into your graveyard from the battlefield, you may pay {2}{B}. If you do, return this card from your graveyard to your hand. Otherwise, exile this card.)

Quag Sickness

Enchant creature
Enchanted creature gets -1/-1 for each Swamp you control.

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.)

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.

Junkyo Bell

At the beginning of your upkeep, you may have target creature you control get +X/+X until end of turn, where X is the number of creatures you control. If you do, sacrifice that creature at the beginning of the next end step.

Murder

Vampiric Touch

Vampiric Touch deals 2 damage to target opponent or planeswalker and you gain 2 life.

Soul Strings

Return two target creature cards from your graveyard to your hand unless any player pays {X}.

Chill to the Bone

Mana Geode

When Mana Geode enters the battlefield, scry 1.
{T}: Add one mana of any color.

Price of Betrayal

Remove up to five counters from target artifact, creature, planeswalker, or opponent.

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Corrupt

Corrupt deals damage to any target equal to the number of Swamps you control. You gain life equal to the damage dealt this way.

Ravenous Rats

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

Rescue from the Underworld

As an additional cost to cast this spell, sacrifice a creature.
Choose target creature card in your graveyard. Return that card and the sacrificed card to the battlefield under your control at the beginning of your next upkeep. Exile Rescue from the Underworld.

Feast of the Unicorn

Enchant creature
Enchanted creature gets +4/+0.

Earsplitting Rats

When Earsplitting Rats enters the battlefield, each player discards a card.
Discard a card: Regenerate Earsplitting Rats.

Soul Burn

Spend only black and/or red mana on X.
Soul Burn deals X damage to any target. You gain life equal to the damage dealt, but not more than the amount of {B} spent on X, the player's life total before the damage was dealt, the planeswalker's loyalty before the damage was dealt, or the creature's toughness.

Rise from the Grave

Put target creature card from a graveyard onto the battlefield under your control. That creature is a black Zombie in addition to its other colors and types.

Deathmask Nezumi

As long as you have seven or more cards in hand, Deathmask Nezumi gets +2/+1 and has fear. (It can't be blocked except by artifact creatures and/or black creatures.)

Marrow-Gnawer

All Rats have fear.
{T}, Sacrifice a Rat: Create X 1/1 black Rat creature tokens, where X is the number of Rats you control.