Unexplained Disappearance

Return target creature to its owner's hand.
Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Thoughtbound Phantasm

Defender
Whenever you surveil, put a +1/+1 counter on Thoughtbound Phantasm.
As long as Thoughtbound Phantasm has three or more +1/+1 counters on it, it can attack as though it didn't have defender.

Lazav, Dimir Mastermind

Hexproof
Whenever a creature card is put into an opponent's graveyard from anywhere, you may have Lazav, Dimir Mastermind become a copy of that card, except its name is Lazav, Dimir Mastermind, it's legendary in addition to its other types, and it has hexproof and this ability.

Shadow Slice

Target opponent loses 3 life.
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.)

Disinformation Campaign

When Disinformation Campaign enters, you draw a card and each opponent discards a card.
Whenever you surveil, return Disinformation Campaign to its owner's hand.

Blood Operative

Lifelink
When Blood Operative enters, you may exile target card from a graveyard.
Whenever you surveil, if Blood Operative is in your graveyard, you may pay 3 life. If you do, return Blood Operative to your hand.

Dimir Infiltrator

Dimir Infiltrator 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 Spybug

Flying
Menace (This creature can't be blocked except by two or more creatures.)
Whenever you surveil, put a +1/+1 counter on Dimir Spybug.

Notion Rain

Surveil 2, then draw two cards. Notion Rain deals 2 damage to you. (To 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.)

Child of Night

Whispering Snitch

Whenever you surveil for the first time each turn, Whispering Snitch deals 1 damage to each opponent and you gain 1 life.

Hired Poisoner

Dimir Cutpurse

Whenever Dimir Cutpurse deals combat damage to a player, that player discards a card and you draw a card.

Dismal Backwater

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {U} or {B}.

Choked Estuary

As Choked Estuary enters, you may reveal an Island or Swamp card from your hand. If you don't, Choked Estuary enters tapped.
{T}: Add {U} or {B}.

Darkblade Agent

As long as you've surveilled this turn, Darkblade Agent has deathtouch and "Whenever this creature deals combat damage to a player, you draw a card."

Nightveil Specter

Flying
Whenever Nightveil Specter deals combat damage to a player, that player exiles the top card of their library.
You may play lands and cast spells from among cards exiled with Nightveil Specter.

Whisper Agent

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

Island

Nightveil Predator

Flying, deathtouch
Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Swamp

Enhanced Surveillance

You may look at an additional two cards each time you surveil.
Exile Enhanced Surveillance: Shuffle your graveyard into your library.

Nightveil Sprite

Flying
Whenever Nightveil Sprite attacks, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Shadowmage Infiltrator

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Whenever Shadowmage Infiltrator deals combat damage to a player, you may draw a card.

Dimir Aqueduct

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