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 this creature.

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 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.

Swamp

Smoldering Marsh

({T}: Add {B} or {R}.)
This land enters tapped unless you control two or more basic lands.

Swarm of Rats

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

Mind Twist

Target player discards X cards at random.

Rakdos Guildgate

This land enters tapped.
{T}: Add {B} or {R}.

Altar's Reap

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

Typhoid Rats

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

Skull Rend

Skull Rend deals 2 damage to each opponent. Those players each discard two cards at random.

Dreadbore

Mountain

Dragonskull Summit

This land enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Sanity Gnawers

When this creature enters, target player discards a card at random.

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.

Ratcatcher

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
At the beginning of your upkeep, you may search your library for a Rat card, reveal it, put it into your hand, then shuffle.

Tainted Peak

{T}: Add {C}.
{T}: Add {B} or {R}. Activate only if you control a Swamp.

Swarmyard

{T}: Add {C}.
{T}: Regenerate target Insect, Rat, Spider, or Squirrel. (The next time it would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Suffering

Pain

Pain // Suffering

Hellhole Rats

Haste
When this creature enters, target player discards a card. This creature deals damage to that player equal to that card's mana value.