Undercity Plague

Target player loses 1 life, discards a card, then sacrifices a permanent.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Disembowel

Destroy target creature with mana value X.

Sins of the Past

Until end of turn, you may cast target instant or sorcery card from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead. Exile Sins of the Past.

Drill Bit

Spectacle {B} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Target player reveals their hand. You choose a nonland card from it. That player discards that card.

Sepulchral Primordial

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
When Sepulchral Primordial enters, for each opponent, you may put up to one target creature card from that player's graveyard onto the battlefield under your control.

Desecration Demon

Flying
At the beginning of each combat, any opponent may sacrifice a creature. If a player does, tap Desecration Demon and put a +1/+1 counter on it.

Grifter's Blade

Flash
As Grifter's Blade enters, choose a creature you control it could be attached to. If you do, it enters attached to that creature.
Equipped creature gets +1/+1.
Equip {1}

Exhumer Thrull

Haunt (When this creature dies, exile it haunting target creature.)
When Exhumer Thrull enters or the creature it haunts dies, return target creature card from your graveyard to your hand.

Slate Street Ruffian

Whenever Slate Street Ruffian becomes blocked, defending player discards a card.

Clear the Stage

Target creature gets -3/-3 until end of turn. If you control a creature with power 4 or greater, you may return up to one target creature card from your graveyard to your hand.

Strands of Undeath

Enchant creature
When Strands of Undeath enters, target player discards two cards.
{B}: Regenerate enchanted creature.

Hired Poisoner

Undercity Shade

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
{B}: Undercity Shade gets +1/+1 until end of turn.

Swamp

Killing Glare

Destroy target creature with power X or less.

Cry of Contrition

Target player discards a card.
Haunt (When this spell card is put into a graveyard after resolving, exile it haunting target creature.)
When the creature Cry of Contrition haunts dies, target player discards a card.

Drainpipe Vermin

When Drainpipe Vermin dies, you may pay {B}. If you do, target player discards a card.

Orzhov Racketeers

Whenever Orzhov Racketeers deals combat damage to a player, that player discards a card.
Afterlife 2 (When this creature dies, create two 1/1 white and black Spirit creature tokens with flying.)

Midnight Reaper

Whenever a nontoken creature you control dies, Midnight Reaper deals 1 damage to you and you draw a card.

Glaring Spotlight

Creatures your opponents control with hexproof can be the targets of spells and abilities you control as though they didn't have hexproof.
{3}, Sacrifice Glaring Spotlight: Creatures you control gain hexproof until end of turn and can't be blocked this turn.

Plaguecrafter

When Plaguecrafter enters, each player sacrifices a creature or planeswalker. Each player who can't discards a card.

Awaken the Erstwhile

Each player discards all the cards in their hand, then creates that many 2/2 black Zombie creature tokens.

Undercity Informer

{1}, Sacrifice a creature: Target player reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.

Mausoleum Secrets

Undergrowth — Search your library for a black card with mana value less than or equal to the number of creature cards in your graveyard, reveal it, put it into your hand, then shuffle.

Gruesome Menagerie

Choose a creature card with mana value 1 in your graveyard, then do the same for creature cards with mana value 2 and 3. Return those cards to the battlefield.

The Haunt of Hightower

Flying, lifelink
Whenever The Haunt of Hightower attacks, defending player discards a card.
Whenever a card is put into an opponent's graveyard from anywhere, put a +1/+1 counter on The Haunt of Hightower.

Crypt Incursion

Exile all creature cards from target player's graveyard. You gain 3 life for each card exiled this way.

Bond of Agony

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

Slum Reaper

When Slum Reaper enters, each player sacrifices a creature.

Restless Bones

{3}{B}, {T}: Target creature gains swampwalk until end of turn. (It can't be blocked as long as defending player controls a Swamp.)
{1}{B}: Regenerate Restless Bones.

Burglar Rat

When Burglar Rat enters, each opponent discards a card.

Grisly Spectacle

Destroy target nonartifact creature. Its controller mills cards equal to that creature's power.

Dying Wish

Enchant creature you control
When enchanted creature dies, target player loses X life and you gain X life, where X is its power.

Dead Revels

Spectacle {1}{B} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Return up to two target creature cards from your graveyard to your hand.

Assassin's Strike

Destroy target creature. Its controller discards a card.

Noxious Groodion

Mind Rot

Crypt Ghast

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}.

Delirium Skeins

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.

Vicious Rumors

Vicious Rumors deals 1 damage to each opponent. Each opponent discards a card, then mills a card. You gain 1 life.

Pestilent Spirit

Menace, deathtouch
Instant and sorcery spells you control have deathtouch. (Any amount of damage they deal to a creature is enough to destroy it.)

Necrotic Wound

Undergrowth — Target creature gets -X/-X until end of turn, where X is the number of creature cards in your graveyard. If that creature would die this turn, exile it instead.

Last Gasp

Target creature gets -3/-3 until end of turn.

Grave Betrayal

Whenever a creature you don't control dies, return it to the battlefield under your control with an additional +1/+1 counter on it at the beginning of the next end step. That creature is a black Zombie in addition to its other colors and types.

Seize the Soul

Destroy target nonwhite, nonblack creature. Create a 1/1 white Spirit creature token with flying.
Haunt (When this spell card is put into a graveyard after resolving, exile it haunting target creature.)
When the creature Seize the Soul haunts dies, destroy target nonwhite, nonblack creature. Create a 1/1 white Spirit creature token with flying.

Perilous Shadow

{1}{B}: Perilous Shadow gets +2/+2 until end of turn.

Illusionist's Bracers

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}

Hissing Miasma

Whenever a creature attacks you, its controller loses 1 life.

Slithering Shade

Defender (This creature can't attack.)
{B}: Slithering Shade gets +1/+1 until end of turn.
Hellbent — Slithering Shade can attack as though it didn't have defender as long as you have no cards in hand.

Balustrade Spy

Flying
When Balustrade Spy enters, target player reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.

Doom Whisperer

Flying, trample
Pay 2 life: Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Wight of Precinct Six

Wight of Precinct Six gets +1/+1 for each creature card in your opponents' graveyards.

Underworld Connections

Enchant land
Enchanted land has "{T}, Pay 1 life: Draw a card."

Thespian's Stage

{T}: Add {C}.
{2}, {T}: Thespian's Stage becomes a copy of target land, except it has this ability.

Unliving Psychopath

{B}: Unliving Psychopath gets +1/-1 until end of turn.
{B}, {T}: Destroy target creature with power less than Unliving Psychopath's power.

Moonlight Bargain

Look at the top five cards of your library. For each card, put that card into your graveyard unless you pay 2 life. Then put the rest into your hand.

Sword of the Paruns

As long as equipped creature is tapped, tapped creatures you control get +2/+0.
As long as equipped creature is untapped, untapped creatures you control get +0/+2.
{3}: You may tap or untap equipped creature.
Equip {3}

Riot Gear

Equipped creature gets +1/+2.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Grim Roustabout

Unleash (You may have this creature enter with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)
{1}{B}: Regenerate Grim Roustabout.

Bladebrand

Target creature gains deathtouch until end of turn.
Draw a card.

Thirsting Shade

Lifelink
{2}{B}: Thirsting Shade gets +1/+1 until end of turn.

Mental Vapors

Target player discards a card.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Skyblinder Staff

Equipped creature gets +1/+0 and can't be blocked by creatures with flying.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Cremate

Exile target card from a graveyard.
Draw a card.

Pilfering Imp

Flying
{1}{B}, {T}, Sacrifice Pilfering Imp: Target opponent reveals their hand. You choose a nonland card from it. That player discards that card. Activate only as a sorcery.

Abyssal Nocturnus

Whenever an opponent discards a card, Abyssal Nocturnus gets +2/+2 and gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)