Unblinking Observer

{T}: Add {U}. Spend this mana only to pay a disturb cost or cast an instant or sorcery spell.

Island

Otherworldly Gaze

Surveil 3. (Look at the top three cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Morning Apparition

Flying, vigilance
If Morning Apparition would be put into a graveyard from anywhere, exile it instead.

Mourning Patrol

Vigilance
Disturb {3}{W} (You may cast this card from your graveyard transformed for its disturb cost.)

Mourning Patrol // Morning Apparition

Plains

Drownyard Amalgam

When Drownyard Amalgam enters the battlefield, target player mills three cards. (They put the top three cards of their library into their graveyard.)
{2}{U}: Drownyard Amalgam can't be blocked this turn.

Generous Soul

Flying, vigilance
If Generous Soul would be put into a graveyard from anywhere, exile it instead.

Beloved Beggar

Disturb {4}{W}{W} (You may cast this card from your graveyard transformed for its disturb cost.)

Beloved Beggar // Generous Soul

Firmament Sage

If it's neither day nor night, it becomes day as Firmament Sage enters the battlefield.
Whenever day becomes night or night becomes day, draw a card.

Adeline, Resplendent Cathar

Vigilance
Adeline, Resplendent Cathar's power is equal to the number of creatures you control.
Whenever you attack, for each opponent, create a 1/1 white Human creature token that's tapped and attacking that player or a planeswalker they control.

Nebelgast Intruder

Flash
Flying
When Nebelgast Intruder enters the battlefield, up to one target creature an opponent controls gets -2/-0 until end of turn.

Dauntless Avenger

Whenever Dauntless Avenger attacks, return target creature card with mana value 2 or less from your graveyard to the battlefield tapped and attacking.

Bereaved Survivor

When another creature you control dies, transform Bereaved Survivor.

Bereaved Survivor // Dauntless Avenger

Teferi, Who Slows the Sunset

+1: Choose up to one target artifact, up to one target creature, and up to one target land. Untap the chosen permanents you control. Tap the chosen permanents you don't control. You gain 2 life.
−2: Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.
−7: You get an emblem with "Untap all permanents you control during each opponent's untap step" and "You draw a card during each opponent's draw step."

Waildrifter

Flying
If Waildrifter would be put into a graveyard from anywhere, exile it instead.

Galedrifter

Flying
Disturb {4}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Galedrifter // Waildrifter

Cathar's Call

Enchant creature
Enchanted creature has vigilance and "At the beginning of your end step, create a 1/1 white Human creature token."

Insectile Aberration

Delver of Secrets

At the beginning of your upkeep, look at the top card of your library. You may reveal that card. If an instant or sorcery card is revealed this way, transform Delver of Secrets.

Delver of Secrets // Insectile Aberration

Falcon Abomination

Flying
When Falcon Abomination enters the battlefield, create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)

Startle

Target creature gets -2/-0 until end of turn. Create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)
Draw a card.

Triskaidekaphile

You have no maximum hand size.
At the beginning of your upkeep, if you have exactly thirteen cards in your hand, you win the game.
{3}{U}: Draw a card.

Candlegrove Witch

Coven — At the beginning of combat on your turn, if you control three or more creatures with different powers, Candlegrove Witch gains flying until end of turn.

Hook-Haunt Drifter

Flying
If Hook-Haunt Drifter would be put into a graveyard from anywhere, exile it instead.

Baithook Angler

Disturb {1}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Baithook Angler // Hook-Haunt Drifter

Sungold Barrage

Destroy target creature with toughness 4 or greater.

Homestead Courage

Put a +1/+1 counter on target creature you control. It gains vigilance until end of turn.
Flashback {W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Celestus Sanctifier

If it's neither day nor night, it becomes day as Celestus Sanctifier enters the battlefield.
Whenever day becomes night or night becomes day, look at the top two cards of your library. Put one of them into your graveyard.

Cathar Commando

Flash
{1}, Sacrifice Cathar Commando: Destroy target artifact or enchantment.

Candletrap

Enchant creature
Enchanted creature has defender.
Prevent all combat damage that would be dealt by enchanted creature.
Coven — {2}{W}, Sacrifice Candletrap: Exile enchanted creature. Activate only if you control three or more creatures with different powers.

Ominous Roost

When Ominous Roost enters the battlefield or whenever you cast a spell from your graveyard, create a 1/1 blue Bird creature token with flying and "This creature can block only creatures with flying."