Helm of the Ghastlord

Enchant creature
As long as enchanted creature is blue, it gets +1/+1 and has "Whenever this creature deals damage to an opponent, draw a card."
As long as enchanted creature is black, it gets +1/+1 and has "Whenever this creature deals damage to an opponent, that player discards a card."

Gorgon Recluse

Whenever Gorgon Recluse blocks or becomes blocked by a nonblack creature, destroy that creature at end of combat.
Madness {B}{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.)

Galvanic Alchemist

Soulbond (You may pair this creature with another unpaired creature when either enters the battlefield. They remain paired for as long as you control both of them.)
As long as Galvanic Alchemist is paired with another creature, each of those creatures has "{2}{U}: Untap this creature."

Desert of the Glorified

Desert of the Glorified enters the battlefield tapped.
{T}: Add {B}.
Cycling {1}{B} ({1}{B}, Discard this card: Draw a card.)

Mistvein Borderpost

You may pay {1} and return a basic land you control to its owner's hand rather than pay this spell's mana cost.
Mistvein Borderpost enters the battlefield tapped.
{T}: Add {U} or {B}.

Oubliette

When Oubliette enters the battlefield, target creature phases out until Oubliette leaves the battlefield. Tap that creature as it phases in this way. (Auras and Equipment phase out with it. While permanents are phased out, they're treated as though they don't exist.)

Traitor's Clutch

Target creature gets +1/+0, becomes black, and gains shadow until end of turn. (It can block or be blocked by only creatures with shadow.)
Flashback {1}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Disciple of Deceit

Inspired — Whenever Disciple of Deceit becomes untapped, you may discard a nonland card. If you do, search your library for a card with the same mana value as that card, reveal it, put it into your hand, then shuffle.

Thriving Isle

Thriving Isle enters the battlefield tapped.
As Thriving Isle enters the battlefield, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

Castaway's Despair

Enchant creature
When Castaway's Despair enters the battlefield, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Psychotic Episode

Target player reveals their hand and the top card of their library. You choose a card revealed this way. That player puts the chosen card on the bottom of their library.
Madness {1}{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.)

Halimar Depths

Halimar Depths enters the battlefield tapped.
When Halimar Depths enters the battlefield, look at the top three cards of your library, then put them back in any order.
{T}: Add {U}.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Warped Landscape

{T}: Add {C}.
{2}, {T}, Sacrifice Warped Landscape: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Dimir Aqueduct

Dimir Aqueduct enters the battlefield tapped.
When Dimir Aqueduct enters the battlefield, return a land you control to its owner's hand.
{T}: Add {U}{B}.

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Counterspell

Scrivener

When Scrivener enters the battlefield, you may return target instant card from your graveyard to your hand.

Archaeomancer

When Archaeomancer enters the battlefield, return target instant or sorcery card from your graveyard to your hand.

Esper Panorama

{T}: Add {C}.
{1}, {T}, Sacrifice Esper Panorama: Search your library for a basic Plains, Island, or Swamp card, put it onto the battlefield tapped, then shuffle.

Freed from the Real

Enchant creature
{U}: Tap enchanted creature.
{U}: Untap enchanted creature.

Witching Well

When Witching Well enters the battlefield, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)
{3}{U}, Sacrifice Witching Well: Draw two cards.

Stonybrook Angler

{1}{U}, {T}: You may tap or untap target creature.

Lonely Sandbar

Lonely Sandbar enters the battlefield tapped.
{T}: Add {U}.
Cycling {U} ({U}, Discard this card: Draw a card.)

Dream's Grip

Choose one —
• Tap target permanent.
• Untap target permanent.
Entwine {1} (Choose both if you pay the entwine cost.)

Dramatic Reversal

Untap all nonland permanents you control.

Dimir Cluestone

{T}: Add {U} or {B}.
{U}{B}, {T}, Sacrifice Dimir Cluestone: Draw a card.

Remote Isle

Remote Isle enters the battlefield tapped.
{T}: Add {U}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Mystical Teachings

Search your library for an instant card or a card with flash, reveal it, put it into your hand, then shuffle.
Flashback {5}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Ice Tunnel

({T}: Add {U} or {B}.)
Ice Tunnel enters the battlefield tapped.

Witness of Tomorrows

Claustrophobia

Enchant creature
When Claustrophobia enters the battlefield, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Charmed Sleep

Enchant creature
When Charmed Sleep enters the battlefield, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Dimir Locket

{T}: Add {U} or {B}.
{U/B}{U/B}{U/B}{U/B}, {T}, Sacrifice Dimir Locket: Draw two cards.

Gray Merchant of Asphodel

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.)

Forbidden Alchemy

Look at the top four cards of your library. Put one of them into your hand and the rest into your graveyard.
Flashback {6}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Polluted Mire

Polluted Mire enters the battlefield tapped.
{T}: Add {B}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Deep Analysis

Target player draws two cards.
Flashback—{1}{U}, Pay 3 life. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Sanitarium Skeleton

{2}{B}: Return Sanitarium Skeleton from your graveyard to your hand.

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.

Mistvault Bridge

Mistvault Bridge enters the battlefield tapped.
Indestructible
{T}: Add {U} or {B}.

Dimir Guildgate

Dimir Guildgate enters the battlefield tapped.
{T}: Add {U} or {B}.

Sky Diamond

Sky Diamond enters the battlefield tapped.
{T}: Add {U}.

Mothdust Changeling

Changeling (This card is every creature type.)
Tap an untapped creature you control: Mothdust Changeling gains flying until end of turn.

Mystic Sanctuary

({T}: Add {U}.)
Mystic Sanctuary enters the battlefield tapped unless you control three or more other Islands.
When Mystic Sanctuary enters the battlefield untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Charcoal Diamond

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

Thriving Moor

Thriving Moor enters the battlefield tapped.
As Thriving Moor enters the battlefield, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Armillary Sphere

{2}, {T}, Sacrifice Armillary Sphere: Search your library for up to two basic land cards, reveal them, put them into your hand, then shuffle.

Desert of the Mindful

Desert of the Mindful enters the battlefield tapped.
{T}: Add {U}.
Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)

World-Weary

Enchant creature
Enchanted creature gets -4/-4.
Basic landcycling {1}{B} ({1}{B}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Dream Fracture

Counter target spell. Its controller draws a card.
Draw a card.

Submerged Boneyard

Submerged Boneyard enters the battlefield tapped.
{T}: Add {U} or {B}.

Displace

Exile up to two target creatures you control, then return those cards to the battlefield under their owner's control.

Barren Moor

Barren Moor enters the battlefield tapped.
{T}: Add {B}.
Cycling {B} ({B}, Discard this card: Draw a card.)

Perplex

Counter target spell unless its controller discards their hand.
Transmute {1}{U}{B} ({1}{U}{B}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Brain Gorgers

When you cast this spell, any player may sacrifice a creature. If a player does, counter Brain Gorgers.
Madness {1}{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.)

Grisly Transformation

Enchant creature
When Grisly Transformation enters the battlefield, draw a card.
Enchanted creature has intimidate. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Unwind

Counter target noncreature spell. Untap up to three lands.

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Mnemonic Wall

Defender
When Mnemonic Wall enters the battlefield, you may return target instant or sorcery card from your graveyard to your hand.

Moan of the Unhallowed

Create two 2/2 black Zombie creature tokens.
Flashback {5}{B}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Dismal Backwater

Dismal Backwater enters the battlefield tapped.
When Dismal Backwater enters the battlefield, you gain 1 life.
{T}: Add {U} or {B}.

Recoil

Return target permanent to its owner's hand. Then that player discards a card.

Salvager of Secrets

When Salvager of Secrets enters the battlefield, return target instant or sorcery card from your graveyard to your hand.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Undertaker

{B}, {T}, Discard a card: Return target creature card from your graveyard to your hand.

Kitchen Imp

Flying, haste
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.)

Grasp of Phantoms

Put target creature on top of its owner's library.
Flashback {7}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Witch's Cottage

({T}: Add {B}.)
Witch's Cottage enters the battlefield tapped unless you control three or more other Swamps.
When Witch's Cottage enters the battlefield untapped, you may put target creature card from your graveyard on top of your library.

Grixis Panorama

{T}: Add {C}.
{1}, {T}, Sacrifice Grixis Panorama: Search your library for a basic Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Chittering Rats

When Chittering Rats enters the battlefield, target opponent puts a card from their hand on top of their library.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Condescend

Counter target spell unless its controller pays {X}. Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

Strands of Undeath

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

Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Banishing Knack

Until end of turn, target creature gains "{T}: Return target nonland permanent to its owner's hand."

Tortured Existence

{B}, Discard a creature card: Return target creature card from your graveyard to your hand.

Mortuary Mire

Mortuary Mire enters the battlefield tapped.
When Mortuary Mire enters the battlefield, you may put target creature card from your graveyard on top of your library.
{T}: Add {B}.

Swamp

Dimir Signet

Grave Scrabbler

Madness {1}{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.)
When Grave Scrabbler enters the battlefield, if its madness cost was paid, you may return target creature card from a graveyard to its owner's hand.