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.

Nashi, Moon Sage's Scion

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 Nashi, Moon Sage's Scion deals combat damage to a player, exile the top card of each player's library. Until end of turn, you may play one of those cards. If you cast a spell this way, pay life equal to its mana value rather than paying its mana cost.

Reliquary Tower

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

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.)

Geier Reach Sanitarium

{T}: Add {C}.
{2}, {T}: Each player draws a card, then discards a card.

Tendrils of Corruption

Tendrils of Corruption deals X damage to target creature and you gain X life, where X is the number of Swamps you control.

Agadeem, the Undercrypt

As Agadeem, the Undercrypt enters the battlefield, you may pay 3 life. If you don't, it enters the battlefield tapped.
{T}: Add {B}.

Agadeem's Awakening

Return from your graveyard to the battlefield any number of target creature cards that each have a different mana value X or less.

Agadeem's Awakening // Agadeem, the Undercrypt

Emergence Zone

{T}: Add {C}.
{1}, {T}, Sacrifice Emergence Zone: You may cast spells this turn as though they had flash.

Command Tower

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

Crypt Rats

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

Shadows of the Past

Whenever a creature dies, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)
{4}{B}: Each opponent loses 2 life and you gain 2 life. Activate only if there are four or more creature cards in your graveyard.

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.

Consuming Vapors

Target player sacrifices a creature. You gain life equal to that creature's toughness.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

The Cruelty of Gix

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I — Target opponent reveals their hand. You choose a creature or planeswalker card from it. That player discards that card.
II — Search your library for a card, put that card into your hand, then shuffle. You lose 3 life.
III — Put target creature card from a graveyard onto the battlefield under your control.

Toxic Deluge

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

Live Fast

You draw two cards, lose 2 life, and get {E}{E} (two energy counters).

Ghost Quarter

{T}: Add {C}.
{T}, Sacrifice Ghost Quarter: Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Nezumi Prowler

Ninjutsu {1}{B} ({1}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
When Nezumi Prowler enters the battlefield, target creature you control gains deathtouch and lifelink until end of turn.

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.

Necrotic Plague

Enchant creature
Enchanted creature has "At the beginning of your upkeep, sacrifice this creature."
When enchanted creature dies, its controller chooses target creature one of their opponents controls. Return Necrotic Plague from its owner's graveyard to the battlefield attached to that creature.

Burglar Rat

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

Plunge into Darkness

Choose one —
• Sacrifice any number of creatures. You gain 3 life for each sacrificed creature.
• Pay X life, then look at the top X cards of your library. Put one of those cards into your hand and exile the rest.
Entwine {B} (Choose both if you pay the entwine cost.)

Demolition Field

{T}: Add {C}.
{2}, {T}, Sacrifice Demolition Field: Destroy target nonbasic land an opponent controls. That land's controller may search their library for a basic land card, put it onto the battlefield, then shuffle. You may search your library for a basic land card, put it onto the battlefield, then shuffle.

Whip of Erebos

Creatures you control have lifelink.
{2}{B}{B}, {T}: Return target creature card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step. If it would leave the battlefield, exile it instead of putting it anywhere else. Activate only as a sorcery.

Phyrexian Arena

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

Lord Skitter's Blessing

When Lord Skitter's Blessing enters the battlefield, create a Wicked Role token attached to target creature you control. (Enchanted creature gets +1/+1. When this Aura is put into a graveyard, each opponent loses 1 life.)
At the beginning of your draw step, if you control an enchanted creature, you lose 1 life and you draw an additional card.

Path of Ancestry

Path of Ancestry enters the battlefield tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Underworld Dreams

Whenever an opponent draws a card, Underworld Dreams deals 1 damage to that player.

Blood for Bones

As an additional cost to cast this spell, sacrifice a creature.
Return a creature card from your graveyard to the battlefield, then return another creature card from your graveyard to your hand.

Bone Shards

As an additional cost to cast this spell, sacrifice a creature or discard a card.
Destroy target creature or planeswalker.

Swamp

Trespasser's Curse

Enchant player
Whenever a creature enters the battlefield under enchanted player's control, that player loses 1 life and you gain 1 life.

Necropotence

Skip your draw step.
Whenever you discard a card, exile that card from your graveyard.
Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.

Persist

Return target nonlegendary creature card from your graveyard to the battlefield with a -1/-1 counter on it.

Fabrication Module

Whenever you get one or more {E} (energy counters), put a +1/+1 counter on target creature you control.
{4}, {T}: You get {E}.

Castle Locthwain

Castle Locthwain enters the battlefield tapped unless you control a Swamp.
{T}: Add {B}.
{1}{B}{B}, {T}: Draw a card, then you lose life equal to the number of cards in your hand.

Pharika's Libation

Choose one —
• Target opponent sacrifices a creature.
• Target opponent sacrifices an enchantment.

Mobilized District

{T}: Add {C}.
{4}: Mobilized District becomes a 3/3 Citizen creature with vigilance until end of turn. It's still a land. This ability costs {1} less to activate for each legendary creature and planeswalker you control.

Blast Zone

Blast Zone enters the battlefield with a charge counter on it.
{T}: Add {C}.
{X}{X}, {T}: Put X charge counters on Blast Zone.
{3}, {T}, Sacrifice Blast Zone: Destroy each nonland permanent with mana value equal to the number of charge counters on Blast Zone.

Lithoform Blight

Enchant land
When Lithoform Blight enters the battlefield, draw a card.
Enchanted land loses all land types and abilities and has "{T}: Add {C}" and "{T}, Pay 1 life: Add one mana of any color."

Bond of Agony

As an additional cost to cast this spell, pay X life.
Each other player loses X life.

Commander's Sphere

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

Reckoner's Bargain

As an additional cost to cast this spell, sacrifice an artifact or creature.
You gain life equal to the sacrificed permanent's mana value. Draw two cards.

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

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.

Charcoal Diamond

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

Flay Essence

Exile target creature or planeswalker. You gain life equal to the number of counters on it.

Sol Ring

Decoction Module

Whenever a creature enters the battlefield under your control, you get {E} (an energy counter).
{4}, {T}: Return target creature you control to its owner's hand.

Ominous Cemetery

{T}: Add {C}.
{5}, {T}, Exile Ominous Cemetery: Target creature's owner shuffles it into their library.

Cremate

Exile target card from a graveyard.
Draw a card.

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.

Bitter Triumph

As an additional cost to cast this spell, discard a card or pay 3 life.
Destroy target creature or planeswalker.

Weatherlight Compleated

Flying
As long as Weatherlight Compleated has four or more phyresis counters on it, it's a Phyrexian creature in addition to its other types.
Whenever a creature you control dies, put a phyresis counter on Weatherlight Compleated. Then draw a card if it has seven or more phyresis counters on it. If it doesn't, scry 1.

Skullsnatcher

Ninjutsu {B} ({B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Skullsnatcher deals combat damage to a player, exile up to two target cards from that player's graveyard.

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.)

Barren Moor

Barren Moor enters the battlefield tapped.
{T}: Add {B}.
Cycling {B} ({B}, Discard this card: Draw a card.)

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.

Vampiric Link

Enchant creature
Whenever enchanted creature deals damage, you gain that much life.

Study Hall

{T}: Add {C}.
{1}, {T}: Add one mana of any color. When you spend this mana to cast your commander, scry X, where X is the number of times it's been cast from the command zone this game.

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.

Mukotai Ambusher

Ninjutsu {1}{B} ({1}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Lifelink

Infernal Reckoning

Exile target colorless creature. You gain life equal to its power.

Blightbelly Rat

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
When Blightbelly Rat dies, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Die Young

Choose target creature. You get {E}{E} (two energy counters), then you may pay any amount of {E}. The creature gets -1/-1 until end of turn for each {E} paid this way.

Vampiric Rites

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

Bojuka Bog

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

Bastion of Remembrance

When Bastion of Remembrance enters the battlefield, create a 1/1 white Human Soldier creature token.
Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.

Cabal Stronghold

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

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.

Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent or discards a card.

Salvaging Station

{T}: Return target noncreature artifact card with mana value 1 or less from your graveyard to the battlefield.
Whenever a creature dies, you may untap Salvaging Station.

Extract the Truth

Choose one —
• Target opponent reveals their hand. You may choose a creature, enchantment, or planeswalker card from it. That player discards that card.
• Target opponent sacrifices an enchantment.

Solar Transformer

Solar Transformer enters the battlefield tapped.
When Solar Transformer enters the battlefield, you get {E}{E}{E} (three energy counters).
{T}: Add {C}.
{T}, Pay {E}: Add one mana of any color.

Rise of the Dark Realms

Put all creature cards from all graveyards onto the battlefield under your control.

Arcane Signet

Thriving Rats

When Thriving Rats enters the battlefield, you get {E}{E} (two energy counters).
Whenever Thriving Rats attacks, you may pay {E}{E}. If you do, put a +1/+1 counter on it.

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.

Nezumi Informant

When Nezumi Informant enters the battlefield, each opponent discards a card.

Sunscorched Desert

When Sunscorched Desert enters the battlefield, it deals 1 damage to target player or planeswalker.
{T}: Add {C}.

Black Market

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

Tribute to Hunger

Target opponent sacrifices a creature. You gain life equal to that creature's toughness.

Karumonix, the Rat King

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Other Rats you control have toxic 1.
When Karumonix enters the battlefield, look at the top five cards of your library. You may reveal any number of Rat cards from among them and put the revealed cards into your hand. Put the rest on the bottom of your library in a random order.

Gnat Miser

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

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.)