Dimir Keyrune

{T}: Add {U} or {B}.
{U}{B}: This artifact becomes a 2/2 blue and black Horror artifact creature until end of turn and can't be blocked this turn.

Ribbons of Night

Ribbons of Night deals 4 damage to target creature and you gain 4 life. If {U} was spent to cast this spell, draw a card.

Dimir Aqueduct

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {U}{B}.

Haunter of Nightveil

Creatures your opponents control get -1/-0.

Vectis Agents

{U}{B}: This creature gets -2/-0 until end of turn and can't be blocked this turn.

Tattered Drake

Dimir Guildgate

This land enters tapped.
{T}: Add {U} or {B}.

Zombie Outlander

Dimir Cluestone

{T}: Add {U} or {B}.
{U}{B}, {T}, Sacrifice this artifact: Draw a card.

Horror of the Dim

{U}: This creature gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Atris, Oracle of Half-Truths

Menace
When Atris enters, target opponent looks at the top three cards of your library and separates them into a face-down pile and a face-up pile. Put one pile into your hand and the other into your graveyard.

Whisper Agent

Flash
When this creature enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Coerced Confession

Target player mills four cards. You draw a card for each creature card put into their graveyard this way.

Mortus Strider

When this creature dies, return it to its owner's hand.

Dimir Infiltrator

This creature can't be blocked.
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.)

Dimir Locket

{T}: Add {U} or {B}.
{U/B}{U/B}{U/B}{U/B}, {T}, Sacrifice this artifact: Draw two cards.

Lurking Informant

({U/B} can be paid with either {U} or {B}.)
{2}, {T}: Look at the top card of target player's library. You may put that card into that player's graveyard.

Paranoid Delusions

Target player mills three cards.
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.)

Psychic Intrusion

Target opponent reveals their hand. You choose a nonland card from that player's graveyard or hand and exile it. You may cast that card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast that spell.

Cavern Harpy

Flying
When this creature enters, return a blue or black creature you control to its owner's hand.
Pay 1 life: Return this creature to its owner's hand.

Soulquake

Return all creatures on the battlefield and all creature cards in graveyards to their owners' hands.

Roofstalker Wight

{1}{U}: This creature gains flying until end of turn.

Tomebound Lich

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
Whenever this creature enters or deals combat damage to a player, draw a card, then discard a card.

Pilfered Plans

Target player mills two cards. Draw two cards.

Dimir Guildmage

({U/B} can be paid with either {U} or {B}.)
{3}{U}: Target player draws a card. Activate only as a sorcery.
{3}{B}: Target player discards a card. Activate only as a sorcery.

Jhessian Zombies

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Islandcycling {2}, swampcycling {2} ({2}, Discard this card: Search your library for an Island or Swamp card, reveal it, put it into your hand, then shuffle.)