Saltskitter

Whenever another creature enters the battlefield, exile Saltskitter. Return Saltskitter to the battlefield under its owner's control at the beginning of the next end step.

Aetherling

{U}: Exile Aetherling. Return it to the battlefield under its owner's control at the beginning of the next end step.
{U}: Aetherling can't be blocked this turn.
{1}: Aetherling gets +1/-1 until end of turn.
{1}: Aetherling gets -1/+1 until end of turn.

Heliod's Emissary

Bestow {6}{W} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Whenever Heliod's Emissary or enchanted creature attacks, tap target creature an opponent controls.
Enchanted creature gets +3/+3.

Steel of the Godhead

Enchant creature
As long as enchanted creature is white, it gets +1/+1 and has lifelink. (Damage dealt by the creature also causes its controller to gain that much life.)
As long as enchanted creature is blue, it gets +1/+1 and can't be blocked.

Peregrine Drake

Flying
When Peregrine Drake enters the battlefield, untap up to five lands.

Whitemane Lion

Flash
When Whitemane Lion enters the battlefield, return a creature you control to its owner's hand.

Momentary Blink

Exile target creature you control, then return it to the battlefield under its owner's control.
Flashback {3}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Rout

You may cast Rout as though it had flash if you pay {2} more to cast it. (You may cast it any time you could cast an instant.)
Destroy all creatures. They can't be regenerated.

Moorland Haunt

{T}: Add {C}.
{W}{U}, {T}, Exile a creature card from your graveyard: Create a 1/1 white Spirit creature token with flying.

Reflector Mage

When Reflector Mage enters the battlefield, return target creature an opponent controls to its owner's hand. That creature's owner can't cast spells with the same name as that creature until your next turn.

Moonlit Scavengers

When Moonlit Scavengers enters the battlefield, if you control an artifact or enchantment, return target creature an opponent controls to its owner's hand.

Flickerwisp

Flying
When Flickerwisp enters the battlefield, exile another target permanent. Return that card to the battlefield under its owner's control at the beginning of the next end step.

So Tiny

Flash
Enchant creature
Enchanted creature gets -2/-0. It gets -6/-0 instead as long as its controller has seven or more cards in their 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}.

Trinket Mage

When Trinket Mage enters the battlefield, you may search your library for an artifact card with mana value 1 or less, reveal that card, put it into your hand, then shuffle.

Azorius Chancery

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

Teferi, Mage of Zhalfir

Flash
Creature cards you own that aren't on the battlefield have flash.
Each opponent can cast spells only any time they could cast a sorcery.

Cursebreak

Destroy target enchantment. You gain 2 life.

Auramancer

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

Restoration Angel

Flash
Flying
When Restoration Angel enters the battlefield, you may exile target non-Angel creature you control, then return that card to the battlefield under your control.

Brine Giant

This spell costs {1} less to cast for each enchantment you control.

Ichthyomorphosis

Enchant creature
Enchanted creature loses all abilities and is a blue Fish with base power and toughness 0/1.

Silent Gravestone

Cards in graveyards can't be the targets of spells or abilities.
{4}, {T}: Exile Silent Gravestone and all cards from all graveyards. Draw a card.

Reverse the Sands

Redistribute any number of players' life totals. (Each of those players gets one life total back.)

Wonder

Flying
As long as Wonder is in your graveyard and you control an Island, creatures you control have flying.

Wave-Wing Elemental

Flying
Landfall — Whenever a land enters the battlefield under your control, Wave-Wing Elemental gets +2/+2 until end of turn.

Omenspeaker

When Omenspeaker 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.)

Indomitable Will

Flash
Enchant creature
Enchanted creature gets +1/+2.

Stonehorn Dignitary

When Stonehorn Dignitary enters the battlefield, target opponent skips their next combat phase.

Scrapdiver Serpent

Scrapdiver Serpent can't be blocked as long as defending player controls an artifact.

Plains

Evolving Wilds

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

Terramorphic Expanse

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

Kasmina, Enigmatic Mentor

Spells your opponents cast that target a creature or planeswalker you control cost {2} more to cast.
−2: Create a 2/2 blue Wizard creature token. Draw a card, then discard a card.

Ephara, God of the Polis

Indestructible
As long as your devotion to white and blue is less than seven, Ephara isn't a creature.
At the beginning of each upkeep, if you had another creature enter the battlefield under your control last turn, draw a card.

Mental Misstep

({U/P} can be paid with either {U} or 2 life.)
Counter target spell with mana value 1.

Venser's Journal

You have no maximum hand size.
At the beginning of your upkeep, you gain 1 life for each card in your hand.

Dissipation Field

Whenever a permanent deals damage to you, return it to its owner's hand.

Heliod's Pilgrim

When Heliod's Pilgrim enters the battlefield, you may search your library for an Aura card, reveal it, put it into your hand, then shuffle.

Lavinia of the Tenth

Protection from red
When Lavinia of the Tenth enters the battlefield, detain each nonland permanent your opponents control with mana value 4 or less. (Until your next turn, those permanents can't attack or block and their activated abilities can't be activated.)

Sky Hussar

Flying
When Sky Hussar enters the battlefield, untap all creatures you control.
Forecast — Tap two untapped white and/or blue creatures you control, Reveal Sky Hussar from your hand: Draw a card. (Activate only during your upkeep and only once each turn.)

Jin-Gitaxias, Core Augur

Flash
At the beginning of your end step, draw seven cards.
Each opponent's maximum hand size is reduced by seven.

Pithing Needle

As Pithing Needle enters the battlefield, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

Eerie Interlude

Exile any number of target creatures you control. Return those cards to the battlefield under their owner's control at the beginning of the next end step.

Reality Acid

Enchant permanent
Vanishing 3 (This Aura enters the battlefield with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Reality Acid leaves the battlefield, enchanted permanent's controller sacrifices it.

Island

Totem-Guide Hartebeest

When Totem-Guide Hartebeest enters the battlefield, you may search your library for an Aura card, reveal it, put it into your hand, then shuffle.

Otherworldly Journey

Exile target creature. At the beginning of the next end step, return that card to the battlefield under its owner's control with a +1/+1 counter on it.

Steelgaze Griffin

Flying
Whenever you draw your second card each turn, Steelgaze Griffin gets +2/+0 until end of turn.

Mnemonic Wall

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

Mulldrifter

Flying
When Mulldrifter enters the battlefield, draw two cards.
Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters the battlefield.)

Rebuke

Aura of Silence

Artifact and enchantment spells your opponents cast cost {2} more to cast.
Sacrifice Aura of Silence: Destroy target artifact or enchantment.

Bronze Sword

Equipped creature gets +2/+0.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Archaeomancer

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

Spectral Searchlight

{T}: Choose a player. That player adds one mana of any color they choose.

Fate Foretold

Enchant creature
When Fate Foretold enters the battlefield, draw a card.
When enchanted creature dies, its controller draws a card.

Incubator Drone

Devoid (This card has no color.)
When Incubator Drone enters the battlefield, create a 1/1 colorless Eldrazi Scion creature token. It has "Sacrifice this creature: Add {C}."

Dreadwaters

Target player mills X cards, where X is the number of lands you control.

Authority of the Consuls

Creatures your opponents control enter the battlefield tapped.
Whenever a creature enters the battlefield under an opponent's control, you gain 1 life.

Sinking Feeling

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.
Enchanted creature has "{1}, Put a -1/-1 counter on this creature: Untap this creature."

Dovin, Grand Arbiter

+1: Until end of turn, whenever a creature you control deals combat damage to a player, put a loyalty counter on Dovin, Grand Arbiter.
−1: Create a 1/1 colorless Thopter artifact creature token with flying. You gain 1 life.
−7: Look at the top ten cards of your library. Put three of them into your hand and the rest on the bottom of your library in a random order.

Portal Mage

Flash
When Portal Mage enters the battlefield during the declare attackers step, you may reselect which player or permanent target attacking creature is attacking. (It can't attack its controller or its controller's planeswalkers.)

Protective Bubble

Enchant creature
Enchanted creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)

Elite Instructor

When Elite Instructor enters the battlefield, draw a card, then discard a card.

Eidolon of Philosophy

{6}{U}, Sacrifice Eidolon of Philosophy: Draw three cards.

Sun Titan

Vigilance
Whenever Sun Titan enters the battlefield or attacks, you may return target permanent card with mana value 3 or less from your graveyard to the battlefield.

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Rupture Spire

Rupture Spire enters the battlefield tapped.
When Rupture Spire enters the battlefield, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Cloudblazer

Flying
When Cloudblazer enters the battlefield, you gain 2 life and draw two cards.

Suture Priest

Whenever another creature enters the battlefield under your control, you may gain 1 life.
Whenever a creature enters the battlefield under an opponent's control, you may have that player lose 1 life.

Karametra's Blessing

Target creature gets +2/+2 until end of turn. If it's an enchanted creature or enchantment creature, it also gains hexproof and indestructible until end of turn. (It can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)