Illusory Ambusher

Flash (You may cast this spell any time you could cast an instant.)
Whenever Illusory Ambusher is dealt damage, draw that many cards.

Mischievous Chimera

Flying
Whenever you cast your first spell during each opponent's turn, Mischievous Chimera deals 1 damage to each opponent. Scry 1.

Dualcaster Mage

Flash
When Dualcaster Mage enters the battlefield, copy target instant or sorcery spell. You may choose new targets for the copy.

Hixus, Prison Warden

Flash (You may cast this spell any time you could cast an instant.)
Whenever a creature deals combat damage to you, if Hixus, Prison Warden entered the battlefield this turn, exile that creature until Hixus leaves the battlefield. (That creature returns under its owner's control.)

Counterspell

Illusionist's Gambit

Cast this spell only during the declare blockers step on an opponent's turn.
Remove all attacking creatures from combat and untap them. After this phase, there is an additional combat phase. Each of those creatures attacks that combat if able. They can't attack you or planeswalkers you control that combat.

Mizzium Meddler

Flash (You may cast this spell any time you could cast an instant.)
When Mizzium Meddler enters the battlefield, you may change a target of target spell or ability to Mizzium Meddler.

Negate

Crafty Cutpurse

Flash
When Crafty Cutpurse enters the battlefield, each token that would be created under an opponent's control this turn is created under your control instead.

Anya, Merciless Angel

Flying
Anya, Merciless Angel gets +3/+3 for each opponent whose life total is less than half their starting life total.
As long as an opponent's life total is less than half their starting life total, Anya has indestructible.

Aven Mindcensor

Flash
Flying
If an opponent would search a library, that player searches the top four cards of that library instead.

Stinging Lionfish

Whenever you cast your first spell during each opponent's turn, you may tap or untap target nonland permanent.

Masako the Humorless

Flash
Tapped creatures you control can block as though they were untapped.

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.

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.

Dream Eater

Flash
Flying
When Dream Eater enters the battlefield, surveil 4. When you do, you may return target nonland permanent an opponent controls to its owner's hand. (To surveil 4, look at the top four cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Alms Collector

Flash
If an opponent would draw two or more cards, instead you and that player each draw a card.

Wavebreak Hippocamp

Whenever you cast your first spell during each opponent's turn, draw a card.

Ancient Stone Idol

Flash
This spell costs {1} less to cast for each attacking creature.
Trample
When Ancient Stone Idol dies, create a 6/12 colorless Construct artifact creature token with trample.

Raff Capashen, Ship's Mage

Flash
Flying
You may cast historic spells as though they had flash. (Artifacts, legendaries, and Sagas are historic.)

Angel of the Dire Hour

Flash
Flying
When Angel of the Dire Hour enters the battlefield, if you cast it from your hand, exile all attacking creatures.

Brineborn Cutthroat

Flash (You may cast this spell any time you could cast an instant.)
Whenever you cast a spell during an opponent's turn, put a +1/+1 counter on Brineborn Cutthroat.

Avacyn, the Purifier

Flying
When this creature transforms into Avacyn, the Purifier, it deals 3 damage to each other creature and each opponent.

Archangel Avacyn

Flash
Flying, vigilance
When Archangel Avacyn enters the battlefield, creatures you control gain indestructible until end of turn.
When a non-Angel creature you control dies, transform Archangel Avacyn at the beginning of the next upkeep.

Archangel Avacyn // Avacyn, the Purifier

Nimble Obstructionist

Flash
Flying
Cycling {2}{U} ({2}{U}, Discard this card: Draw a card.)
When you cycle Nimble Obstructionist, counter target activated or triggered ability you don't control.

Hushwing Gryff

Flash
Flying
Creatures entering the battlefield don't cause abilities to trigger.

Containment Priest

Flash
If a nontoken creature would enter the battlefield and it wasn't cast, exile it instead.

Draining Whelk

Flash
Flying
When Draining Whelk enters the battlefield, counter target spell. Put X +1/+1 counters on Draining Whelk, where X is that spell's mana value.

Izzet Staticaster

Flash (You may cast this spell any time you could cast an instant.)
Haste
{T}: Izzet Staticaster deals 1 damage to target creature and each other creature with the same name as that creature.

Dreamstalker Manticore

Whenever you cast your first spell during each opponent's turn, Dreamstalker Manticore deals 1 damage to any target.