Whenever Ayara, First of Locthwain or another black creature enters the battlefield under your control, each opponent loses 1 life and you gain 1 life. {T}, Sacrifice another black creature: Draw a card.

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.)

As Cover of Darkness enters the battlefield, choose a creature type. Creatures of the chosen type have fear. (They can't be blocked except by artifact creatures and/or black creatures.)

Creatures you control have haste. (They can attack and {T} as soon as they come under your control.)

Choose a creature type. For each creature you control of the chosen type, create a token that's a copy of that creature. Those tokens gain haste. Exile them at the beginning of the next end step.

({T}: Add {R}.)

Cumulative upkeep—Add {R}. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.) Whenever you tap a Swamp for mana, add an additional {B}.

Add {B}{B}{B}.

Activated abilities of creatures cost {1} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Whenever an ability of equipped creature is activated, if it isn't a mana ability, copy that ability. You may choose new targets for the copy. Equip {3}

Choose one. If you control a commander as you cast this spell, you may choose both instead. • Add {R} for each card in target opponent's hand. • Exile the top three cards of your library. You may play them this turn.

Whenever a creature enters the battlefield, you may add an amount of {C} equal to the number of creatures you control that share a creature type with it.

Add {R} for each tapped land your opponents control.

Nyx Lotus enters the battlefield tapped. {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

When Priest of Gix enters the battlefield, add {B}{B}{B}.

When Priest of Urabrask enters the battlefield, add {R}{R}{R}.

({T}: Add {B} or {R}.) As Blood Crypt enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

{2}, {T}: Add {B} for each Swamp you control.

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

Dragonskull Summit enters the battlefield tapped unless you control a Swamp or a Mountain. {T}: Add {B} or {R}.

{T}: Add {C}. {B/R}, {T}: Add {B}{B}, {B}{R}, or {R}{R}.

Luxury Suite enters the battlefield tapped unless you have two or more opponents. {T}: Add {B} or {R}.

{T}: Add {C}. {2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

{T}: Add {C}. {T}: Add {B} or {R}. Sulfurous Springs deals 1 damage to you.

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

Whenever Ashcoat of the Shadow Swarm attacks or blocks, other Rats you control get +X/+X until end of turn, where X is the number of Rats you control. At the beginning of your end step, you may mill four cards. If you do, return up to two Rat creature cards from your graveyard to your hand. (To mill a card, put the top card of your library into your graveyard.)

Discard a card: You may cast a creature spell from your graveyard this turn. Activate only once each turn. Whenever a nontoken creature enters the battlefield under your control, if you didn't cast it from your hand, it gains haste until your next turn.

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.

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.

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

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.

Whenever Totentanz, Swarm Piper or another nontoken creature you control dies, create a 1/1 black Rat creature token with "This creature can't block." {1}{B}: Target attacking Rat you control gains deathtouch until end of turn.

Whenever one or more creature cards leave your graveyard, create a 1/1 black Bat creature token with flying.

Flying Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.) {2}: Put target card from a graveyard on the bottom of its owner's library.

At the beginning of each player's draw step, that player puts the cards in their hand on the bottom of their library in any order, then draws that many cards.

This spell costs {2} less to cast for each creature card in your graveyard. Whenever a creature you control dies, put it on the bottom of its owner's library. {2}{B}, {T}, Pay 2 life: Return target creature card from your graveyard to the battlefield. Activate only as a sorcery.

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.)

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.