Thrumming Stone

Spells you cast have ripple 4. (Whenever you cast a spell, you may reveal the top four cards of your library. You may cast spells with the same name as that spell from among the revealed cards without paying their mana costs. Put the rest on the bottom of your library.)

Foul-Tongue Shriek

Target opponent loses 1 life for each attacking creature you control. You gain that much life.

Jet Medallion

Black spells you cast cost {1} less to cast.

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.)

Vampiric Rites

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

Lightning Greaves

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

Patriarch's Bidding

Each player chooses a creature type. Each player returns all creature cards of a type chosen this way from their graveyard to the battlefield.

Diabolic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Swamp

Attrition

{B}, Sacrifice a creature: Destroy target nonblack creature.

Ogre Slumlord

Whenever another nontoken creature dies, you may create a 1/1 black Rat creature token.
Rats you control have deathtouch.

Dark Prophecy

Whenever a creature you control dies, you draw a card and you lose 1 life.

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.

Living Death

Each player exiles all creature cards from their graveyard, then sacrifices all creatures they control, then puts all cards they exiled this way onto the battlefield.

Lich-Knights' Conquest

Sacrifice any number of artifacts, enchantments, and/or tokens. Return that many creature cards from your graveyard to the battlefield.

Echoing Return

Return target creature card and all other cards with the same name as that card from your graveyard to your hand.

Herald's Horn

As Herald's Horn enters the battlefield, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Thought Vessel

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

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."

Death Denied

Return X target creature cards from your graveyard to your hand.

Swiftfoot Boots

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

Slaughter Pact

Destroy target nonblack creature.
At the beginning of your next upkeep, pay {2}{B}. If you don't, you lose the game.

Thornbite Staff

Equipped creature has "{2}, {T}: This creature deals 1 damage to any target" and "Whenever a creature dies, untap this creature."
Whenever a Shaman creature enters the battlefield, you may attach Thornbite Staff to it.
Equip {4}

Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Scheming Symmetry

Choose two target players. Each of them searches their library for a card, then shuffles and puts that card on top.

Rat Colony

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