Underworld Connections

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

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

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}

Black Cat

When Black Cat dies, target opponent discards a card at random.

Disciple of Phenax

When Disciple of Phenax enters, target player reveals a number of cards from their hand equal to your devotion to black. You choose one of them. That player discards that card. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Dark Privilege

Enchant creature
Enchanted creature gets +1/+1.
Sacrifice a creature: Regenerate enchanted creature.

Burglar Rat

When this creature enters, each opponent discards a card.

Bone Shredder

Flying
Echo {2}{B} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When Bone Shredder enters, destroy target nonartifact, nonblack creature.

Grim Haruspex

Morph {B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
Whenever another nontoken creature you control dies, draw a card.

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Mesmeric Fiend

When Mesmeric Fiend enters, target opponent reveals their hand and you choose a nonland card from it. Exile that card.
When Mesmeric Fiend leaves the battlefield, return the exiled card to its owner's hand.

Pilgrim's Eye

Flying
When Pilgrim's Eye enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Fell Specter

Flying
When Fell Specter enters, target opponent discards a card.
Whenever an opponent discards a card, that player loses 2 life.

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.)

Kaya's Ghostform

Enchant creature or planeswalker you control
When enchanted permanent dies or is put into exile, return that card to the battlefield under your control.

Cadaver Imp

Flying
When Cadaver Imp enters, you may return target creature card from your graveyard to your hand.

Fetid Imp

Flying
{B}: Fetid Imp gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)

Davriel, Rogue Shadowmage

At the beginning of each opponent's upkeep, if that player has one or fewer cards in hand, Davriel, Rogue Shadowmage deals 2 damage to them.
−1: Target player discards a card.

Thallid Soothsayer

Skyscanner

Flying
When Skyscanner enters, draw a card.

Overeager Apprentice

Discard a card, Sacrifice Overeager Apprentice: Add {B}{B}{B}.

Spark Harvest

As an additional cost to cast this spell, sacrifice a creature or pay {3}{B}.
Destroy target creature or planeswalker.

Butcher of Malakir

Flying
Whenever Butcher of Malakir or another creature you control dies, each opponent sacrifices a creature of their choice.

Walking Atlas

{T}: You may put a land card from your hand onto the battlefield.

Fallen Ideal

Enchant creature
Enchanted creature has flying and "Sacrifice a creature: This creature gets +2/+1 until end of turn."
When Fallen Ideal is put into a graveyard from the battlefield, return Fallen Ideal to its owner's hand.

Mindlash Sliver

All Slivers have "{1}, Sacrifice this permanent: Each player discards a card."

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Shirei, Shizo's Caretaker

Whenever a creature with power 1 or less is put into your graveyard from the battlefield, you may return that card to the battlefield at the beginning of the next end step if Shirei, Shizo's Caretaker is still on the battlefield.

Dutiful Attendant

When Dutiful Attendant dies, return another target creature card from your graveyard to your hand.

Plague Myr

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{T}: Add {C}.

Blood Pet

Ashen-Skin Zubera

When Ashen-Skin Zubera dies, target opponent discards a card for each Zubera that died this turn.

Swamp

Pawn of Ulamog

Whenever Pawn of Ulamog or another nontoken creature you control dies, you may create a 0/1 colorless Eldrazi Spawn creature token. It has "Sacrifice this creature: Add {C}."

Charcoal Diamond

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

Quest for the Nihil Stone

Whenever an opponent discards a card, you may put a quest counter on Quest for the Nihil Stone.
At the beginning of each opponent's upkeep, if that player has no cards in hand and Quest for the Nihil Stone has two or more quest counters on it, you may have that player lose 5 life.

Megrim

Whenever an opponent discards a card, Megrim deals 2 damage to that player.

Harvester of Souls

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever another nontoken creature dies, you may draw a card.

Stinkweed Imp

Flying
Whenever Stinkweed Imp deals combat damage to a creature, destroy that creature.
Dredge 5 (If you would draw a card, you may mill five cards instead. If you do, return this card from your graveyard to your hand.)

Vampiric Rites

{1}{B}, Sacrifice a creature: You gain 1 life and draw a card.

Priest of Forgotten Gods

{T}, Sacrifice two other creatures: Any number of target players each lose 2 life and sacrifice a creature of their choice. You add {B}{B} and draw a card.

Noxious Toad

When Noxious Toad dies, each opponent discards a card.

Shrieking Affliction

At the beginning of each opponent's upkeep, if that player has one or fewer cards in hand, they lose 3 life.

Gleaming Barrier

Defender
When this creature dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Mindless Automaton

Mindless Automaton enters with two +1/+1 counters on it.
{1}, Discard a card: Put a +1/+1 counter on Mindless Automaton.
Remove two +1/+1 counters from Mindless Automaton: Draw a card.

Bloodthrone Vampire

Sacrifice a creature: Bloodthrone Vampire gets +2/+2 until end of turn.

Thieving Sprite

Flying
When Thieving Sprite enters, target player reveals X cards from their hand, where X is the number of Faeries you control. You choose one of those cards. That player discards that card.

Leaden Myr

Hedron Crawler

{T}: Add {C}. ({C} represents colorless mana.)

Carrion Feeder

Carrion Feeder can't block.
Sacrifice a creature: Put a +1/+1 counter on Carrion Feeder.

Ravenous Rats

When Ravenous Rats enters, target opponent discards a card.

Crux of Fate

Choose one —
• Destroy all Dragon creatures.
• Destroy all non-Dragon creatures.

Manakin

Nevinyrral's Disk

Nevinyrral's Disk enters tapped.
{1}, {T}: Destroy all artifacts, creatures, and enchantments.

Dusk Legion Zealot

When Dusk Legion Zealot enters, you draw a card and you lose 1 life.

Wheel of Torture

At the beginning of each opponent's upkeep, Wheel of Torture deals X damage to that player, where X is 3 minus the number of cards in their hand.

Yarok's Fenlurker

When Yarok's Fenlurker enters, each opponent exiles a card from their hand.
{2}{B}: Yarok's Fenlurker gets +1/+1 until end of turn.

Deathbringer Regent

Flying
When Deathbringer Regent enters, if you cast it from your hand and there are five or more other creatures on the battlefield, destroy all other creatures.

Abyssal Gatekeeper

When Abyssal Gatekeeper dies, each player sacrifices a creature of their choice.

Dark Prophecy

Whenever a creature you control dies, you draw a card and you lose 1 life.

Royal Assassin

Smothering Abomination

Devoid (This card has no color.)
Flying
At the beginning of your upkeep, sacrifice a creature.
Whenever you sacrifice a creature, draw a card.

Mask of Avacyn

Equipped creature gets +1/+2 and has hexproof. (It can't be the target of spells or abilities your opponents control.)
Equip {3}

Death Denied

Return X target creature cards from your graveyard to your hand.

Raiders' Wake

Whenever an opponent discards a card, that player loses 2 life.
Raid — At the beginning of your end step, if you attacked this turn, target opponent discards a card.