Snarling Gorehound

Menace
Whenever another creature you control with power 2 or less enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Cast Down

Island

Unauthorized Exit

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

Whispering Snitch

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

Swamp

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}.

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

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.

Drowned Catacomb

Drowned Catacomb enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Undercity Sewers

({T}: Add {U} or {B}.)
Undercity Sewers enters tapped.
When Undercity Sewers enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Nightveil Sprite

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

Pile On

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Destroy target creature or planeswalker. 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.)

Thought Erasure

Target opponent reveals their hand. You choose a nonland card from it. That player discards that card.
Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

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.

Doom Whisperer

Flying, trample
Pay 2 life: 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.)