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

{2}, Exile Cranial Archive: Target player shuffles their graveyard into their library. Draw a card.

Equipped creature has double strike. (It deals both first-strike and regular combat damage.) Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Equipped creature has deathtouch. Whenever equipped creature deals combat damage to a player, that player loses half their life, rounded up. Equip {3}

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

Changeling (This card is every creature type.) Changeling Outcast can't block and can't be blocked.

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

When Gray Merchant of Asphodel enters the battlefield, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

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.

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

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

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.

Rats you control have menace. {1}{B}, {T}: Create a 1/1 black Rat creature token. {2}{B}{B}, {T}, Sacrifice three Rats: Gain control of target creature.

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

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.

Relentless Rats gets +1/+1 for each other creature on the battlefield named Relentless Rats. A deck can have any number of cards named Relentless Rats.

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

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.) Whenever Septic Rats attacks, if defending player is poisoned, it gets +1/+1 until end of turn.

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.

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

Changeling (This card is every creature type.) Deathtouch

At the beginning of your upkeep, each player discards a card. Each opponent who discarded a card that shares a card type with the card you discarded loses 3 life. (Players reveal the discarded cards simultaneously.)

Whenever an opponent discards a card, that player loses 2 life.

At the beginning of your upkeep, if twenty or more creature cards are in your graveyard, you win the game.

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

Destroy target nonlegendary creature.

Target creature gets +1/+2 and gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)

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

Target creature gets -2/-2 until end of turn.

Target creature gets -4/-4 until end of turn.

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

Destroy target creature.

Crypt of Agadeem enters the battlefield tapped. {T}: Add {B}. {2}, {T}: Add {B} for each black creature card in your graveyard.

Myriad Landscape enters the battlefield tapped. {T}: Add {C}. {2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Target opponent reveals their hand. You choose a card from it with mana value 4 or greater and exile that card.

Put target artifact or creature card from a graveyard onto the battlefield under your control. Shuffle Beacon of Unrest into its owner's library.

As an additional cost to cast this spell, sacrifice a creature. Destroy target creature.

Target opponent reveals their hand. You choose a creature or planeswalker card from it. That player discards that card.

Destroy target land. Its controller reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.

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

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.

Choose one — • Return target creature card from your graveyard to your hand. • Return two target creature cards that share a creature type from your graveyard to your hand.

Return target creature card with mana value X or less from your graveyard to the battlefield.

Each other player discards a card. You draw a card for each card discarded this way.

Return target creature card with mana value 3 or less from your graveyard to the battlefield. Cycling {2} ({2}, Discard this card: Draw a card.)