Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.

Nightshade Stinger

Pulse Tracker

Whenever this creature attacks, each opponent loses 1 life.

King's Assassin

{T}: Destroy target tapped creature. Activate only during your turn, before attackers are declared.

Doom Blade

Parasitic Grasp

Cleave {1}{B}{B} (You may cast this spell for its cleave cost. If you do, remove the words in square brackets.)
Parasitic Grasp deals 3 damage to target [Human] creature. You gain 3 life.

Phyrexian Tower

{T}: Add {C}.
{T}, Sacrifice a creature: Add {B}{B}.

Assassin Initiate

{1}: Assassin Initiate gains your choice of flying, deathtouch, or lifelink until end of turn.

Stronghold Assassin

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

Downwind Ambusher

Flash
When Downwind Ambusher enters, choose one —
• Target creature an opponent controls gets -1/-1 until end of turn.
• Destroy target creature an opponent controls that was dealt damage this turn.

Safana, Calimport Cutthroat

Menace
At the beginning of your end step, if you have the initiative, create a Treasure token. Create three of those tokens instead if you've completed a dungeon.
Choose a Background (You can have a Background as a second commander.)

Bontu's Monument

Black creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, each opponent loses 1 life and you gain 1 life.

Douse in Gloom

Douse in Gloom deals 2 damage to target creature and you gain 2 life.

Delif's Cone

{T}, Sacrifice Delif's Cone: This turn, when target creature you control attacks and isn't blocked, you may gain life equal to its power. If you do, it assigns no combat damage this turn.

Sol Ring

Delif's Cube

{2}, {T}: This turn, when target creature you control attacks and isn't blocked, it assigns no combat damage this turn and you put a cube counter on Delif's Cube.
{2}, Remove a cube counter from Delif's Cube: Regenerate target creature.

Black Market

Whenever a creature dies, put a charge counter on Black Market.
At the beginning of your first main phase, add {B} for each charge counter on Black Market.

Blightwing Bandit

Flying, deathtouch
Whenever you cast your first spell during each opponent's turn, look at the top card of that player's library, then exile it face down. You may play that card for as long as it remains exiled, and mana of any type can be spent to cast it.

Crypt of Agadeem

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

Hollow Marauder

This spell costs {1} less to cast for each creature card in your graveyard.
Flying
When Hollow Marauder enters, any number of target opponents each discard a card. For each of those opponents who didn't discard a card with mana value 4 or greater, draw a card.

Royal Assassin

Force of Despair

If it's not your turn, you may exile a black card from your hand rather than pay this spell's mana cost.
Destroy all creatures that entered this turn.

Auntie's Snitch

Auntie's Snitch can't block.
Prowl {1}{B} (You may cast this for its prowl cost if you dealt combat damage to a player this turn with a Goblin or Rogue.)
Whenever a Goblin or Rogue you control deals combat damage to a player, if Auntie's Snitch is in your graveyard, you may return Auntie's Snitch to your hand.

Brotherhood Regalia

Equipped creature has ward {2}, is an Assassin in addition to its other types, and can't be blocked.
Equip legendary creature {1}
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Vicious Hunger

Vicious Hunger deals 2 damage to target creature and you gain 2 life.

Termination Facilitator

{T}: Put a bounty counter on target creature or planeswalker. Activate only as a sorcery.
Whenever a creature or planeswalker an opponent controls with a bounty counter on it is dealt damage, destroy it.

Vampire Cutthroat

Skulk (This creature can't be blocked by creatures with greater power.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Bog Smugglers

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Scarblade Elite

{T}, Exile an Assassin card from your graveyard: Destroy target creature.

Night Market Lookout

Whenever Night Market Lookout becomes tapped, each opponent loses 1 life and you gain 1 life.

Stingblade Assassin

Flash
Flying
When Stingblade Assassin enters, destroy target creature an opponent controls that was dealt damage this turn.

Brotherhood Patriarch

When Brotherhood Patriarch dies, each opponent loses 2 life and you gain 2 life.

Discreet Retreat

Enchant land
Enchanted land has "{T}: Add two mana of any one color. Spend this mana only to cast outlaw spells or activate abilities of outlaw sources." (Assassins, Mercenaries, Pirates, Rogues, and Warlocks are outlaws.)
Whenever you cast your first outlaw spell each turn, you draw a card and you lose 1 life.

Doomed Necromancer

{B}, {T}, Sacrifice Doomed Necromancer: Return target creature card from your graveyard to the battlefield.

Clockwork Droid

You may exert Clockwork Droid as it attacks. When you do, it can't be blocked this turn and you scry 1. (An exerted creature won't untap during your next untap step. To scry 1, look at the top card of your library. You may put that card on the bottom.)

Thieves' Tools

When Thieves' Tools enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Equipped creature can't be blocked as long as its power is 3 or less.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Command Beacon

{T}: Add {C}.
{T}, Sacrifice Command Beacon: Put your commander into your hand from the command zone.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Cloak and Dagger

Equipped creature gets +2/+0 and has shroud. (It can't be the target of spells or abilities.)
Whenever a Rogue creature enters, you may attach Cloak and Dagger to it.
Equip {3}

Blade Juggler

Spectacle {2}{B} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
When Blade Juggler enters, it deals 1 damage to you and you draw a card.

Nocturnal Feeder

Flying
When Nocturnal Feeder dies, each opponent loses 2 life and you gain 2 life.

Alley Strangler

Shizo, Death's Storehouse

{T}: Add {B}.
{B}, {T}: Target legendary creature gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)

Prickly Boggart

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

Ravine Raider

Menace (This creature can't be blocked except by two or more creatures.)
{1}{B}: Ravine Raider gets +1/+1 until end of turn.

Dauthi Mercenary

Shadow (This creature can block or be blocked by only creatures with shadow.)
{1}{B}: Dauthi Mercenary gets +1/+0 until end of turn.

Winter's Intervention

Winter's Intervention deals 2 damage to target creature. You gain 2 life.

Back in Town

Return X target outlaw creature cards from your graveyard to the battlefield. (Assassins, Mercenaries, Pirates, Rogues, and Warlocks are outlaws.)

Body Launderer

Deathtouch
Whenever another nontoken creature you control dies, Body Launderer connives.
When Body Launderer dies, return another target non-Rogue creature card with equal or lesser power from your graveyard to the battlefield.

Audacious Thief

Whenever Audacious Thief attacks, you draw a card and you lose 1 life.

Viridian Longbow

Equipped creature has "{T}: This creature deals 1 damage to any target."
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery. This card enters unattached and stays on the battlefield if the creature leaves.)

Blood Money

Destroy all creatures. For each nontoken creature destroyed this way, you create a tapped Treasure token.

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.

Abyssal Hunter

{B}, {T}: Tap target creature. Abyssal Hunter deals damage equal to Abyssal Hunter's power to that creature.

Revel in Riches

Whenever a creature an opponent controls dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
At the beginning of your upkeep, if you control ten or more Treasures, you win the game.

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.

Boggart Loggers

Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)
{2}{B}, Sacrifice Boggart Loggers: Destroy target Treefolk or Forest.

Undercity Scrounger

{T}: Create a Treasure token. Activate only if a creature died this turn. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Sorin's Thirst

Sorin's Thirst deals 2 damage to target creature and you gain 2 life.

Mari, the Killing Quill

Whenever a creature an opponent controls dies, exile it with a hit counter on it.
Assassins, Mercenaries, and Rogues you control have deathtouch and "Whenever this creature deals combat damage to a player, you may remove a hit counter from a card that player owns in exile. If you do, draw a card and create two Treasure tokens."

Garza's Assassin

Sacrifice Garza's Assassin: Destroy target nonblack creature.
Recover—Pay half your life, rounded up. (When another creature is put into your graveyard from the battlefield, you may pay half your life, rounded up. If you do, return this card from your graveyard to your hand. Otherwise, exile this card.)

Morbid Opportunist

Whenever one or more other creatures die, draw a card. This ability triggers only once each turn.

Final-Sting Faerie

Flying
When Final-Sting Faerie enters, destroy target creature that was dealt damage this turn.

Bear Trap

Flash
{3}, {T}, Sacrifice Bear Trap: It deals 3 damage to target creature.

Hoard Robber

Whenever Hoard Robber deals combat damage to a player, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Pathway Arrows

Equipped creature has "{2}, {T}: This creature deals 1 damage to target creature. If a colorless creature is dealt damage this way, tap it."
Equip {2}

Heart-Piercer Bow

Whenever equipped creature attacks, Heart-Piercer Bow deals 1 damage to target creature defending player controls.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Forsaken Miner

Forsaken Miner can't block.
Whenever you commit a crime, you may pay {B}. If you do, return Forsaken Miner from your graveyard to the battlefield. (Targeting opponents, anything they control, and/or cards in their graveyards is a crime.)

Revel Ruiner

Menace (This creature can't be blocked except by two or more creatures.)
When Revel Ruiner enters, it connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Agate-Blade Assassin

Whenever Agate-Blade Assassin attacks, defending player loses 1 life and you gain 1 life.

Rooftop Assassin

Flash
Flying, lifelink
When Rooftop Assassin enters, destroy target creature an opponent controls that was dealt damage this turn.

Big Game Hunter

When Big Game Hunter enters, destroy target creature with power 4 or greater. It can't be regenerated.
Madness {B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Essence Extraction

Essence Extraction deals 3 damage to target creature and you gain 3 life.

Swamp

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Dead Reckoning

You may put target creature card from your graveyard on top of your library. If you do, Dead Reckoning deals damage equal to that card's power to target creature.

Brotherhood Ambushers

Freerunning {3}{B} (You may cast this spell for its freerunning cost if you dealt combat damage to a player this turn with an Assassin or commander.)

Bullwhip

{2}, {T}: Bullwhip deals 1 damage to target creature. That creature attacks this turn if able.

Merrow Bonegnawer

{T}: Target player exiles a card from their graveyard.
Whenever you cast a black spell, you may untap Merrow Bonegnawer.