Leyline of Anticipation

If Leyline of Anticipation is in your opening hand, you may begin the game with it on the battlefield.
You may cast spells as though they had flash.

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.

Elder Deep-Fiend

Flash
Emerge {5}{U}{U} (You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's mana value.)
When you cast this spell, tap up to four target permanents.

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.

Minion's Return

Flash
Enchant creature
When enchanted creature dies, return that card to the battlefield under your control.

Faerie Vandal

Flash (You may cast this spell any time you could cast an instant.)
Flying
Whenever you draw your second card each turn, put a +1/+1 counter on Faerie Vandal.

Torrential Gearhulk

Flash
When Torrential Gearhulk enters, you may cast target instant card from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Lawmage's Binding

Flash
Enchant creature
Enchanted creature can't attack or block, and its activated abilities can't be activated.

Angel of the Dire Hour

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

Hushwing Gryff

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

Crafty Cutpurse

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

Soaring Thought-Thief

Flash
Flying
As long as an opponent has eight or more cards in their graveyard, Rogues you control get +1/+0.
Whenever one or more Rogues you control attack, each opponent mills two cards.

Zareth San, the Trickster

Flash
{2}{U}{B}, Return an unblocked attacking Rogue you control to its owner's hand: Put Zareth San, the Trickster from your hand onto the battlefield tapped and attacking.
Whenever Zareth San deals combat damage to a player, you may put target permanent card from that player's graveyard onto the battlefield under your control.

Spectral Sailor

Flash (You may cast this spell any time you could cast an instant.)
Flying
{3}{U}: Draw a card.

Bloodcrazed Paladin

Flash
Bloodcrazed Paladin enters with a +1/+1 counter on it for each creature that died this turn.

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.

Omen of the Sea

Flash (You may cast this spell any time you could cast an instant.)
When Omen of the Sea enters, scry 2, then draw a card.
{2}{U}, Sacrifice Omen of the Sea: Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Breaking Wave

You may cast Breaking Wave as though it had flash if you pay {2} more to cast it. (You may cast it any time you could cast an instant.)
Simultaneously untap all tapped creatures and tap all untapped creatures.

Hollowhenge Spirit

Flash (You may cast this spell any time you could cast an instant.)
Flying
When Hollowhenge Spirit enters, remove target attacking or blocking creature from combat.

Seal Away

Flash
When Seal Away enters, exile target tapped creature an opponent controls until Seal Away leaves the battlefield.

Draining Whelk

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

Silumgar Sorcerer

Flash (You may cast this spell any time you could cast an instant.)
Flying
Exploit (When this creature enters, you may sacrifice a creature.)
When Silumgar Sorcerer exploits a creature, counter target creature spell.

Voracious Greatshark

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, counter target artifact or creature spell.

Mystic Subdual

Flash
Enchant creature
Enchanted creature gets -2/-0 and loses all abilities. (Mutating onto the creature won't give it new abilities. It can gain abilities in other ways.)

Pouncing Shoreshark

Mutate {3}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flash
Whenever this creature mutates, you may return target creature an opponent controls to its owner's hand.

Mutual Destruction

This spell has flash as long as you control a permanent with flash.
As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature.

Tidal Barracuda

Any player may cast spells as though they had flash.
Your opponents can't cast spells during your turn.

Venser, Shaper Savant

Flash (You may cast this spell any time you could cast an instant.)
When Venser, Shaper Savant enters, return target spell or permanent to its owner's hand.

Emergence Zone

{T}: Add {C}.
{1}, {T}, Sacrifice Emergence Zone: You may cast spells this turn as though they had flash.

Niambi, Esteemed Speaker

Flash
When Niambi, Esteemed Speaker enters, you may return another target creature you control to its owner's hand. If you do, you gain life equal to that creature's mana value.
{1}{W}{U}, {T}, Discard a legendary card: Draw two cards.

Merfolk Trickster

Flash
When Merfolk Trickster enters, tap target creature an opponent controls. It loses all abilities until end of turn.

Lurking Deadeye

Flash
When Lurking Deadeye enters, destroy target creature that was dealt damage this turn.

Omen of the Dead

Flash
When Omen of the Dead enters, return target creature card from your graveyard to your hand.
{2}{B}, Sacrifice Omen of the Dead: Scry 2.

Blacklance Paragon

Flash
When Blacklance Paragon enters, target Knight gains deathtouch and lifelink until end of turn.

Masked Blackguard

Flash (You may cast this spell any time you could cast an instant.)
{2}{B}: Masked Blackguard gets +1/+1 until end of turn.

Stunt Double

Flash
You may have Stunt Double enter as a copy of any creature on the battlefield.

Angel of Grace

Flash
Flying
When Angel of Grace enters, until end of turn, damage that would reduce your life total to less than 1 reduces it to 1 instead.
{4}{W}{W}, Exile Angel of Grace from your graveyard: Your life total becomes 10.

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.

Teferi, Time Raveler

Each opponent can cast spells only any time they could cast a sorcery.
+1: Until your next turn, you may cast sorcery spells as though they had flash.
−3: Return up to one target artifact, creature, or enchantment to its owner's hand. Draw a card.

Dictate of Kruphix

Flash (You may cast this spell any time you could cast an instant.)
At the beginning of each player's draw step, that player draws an additional card.

Muck Drubb

Flash
When Muck Drubb enters, change the target of target spell that targets only a single creature to Muck Drubb.
Madness {2}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Thieves' Guild Enforcer

Flash
Whenever Thieves' Guild Enforcer or another Rogue you control enters, each opponent mills two cards.
As long as an opponent has eight or more cards in their graveyard, Thieves' Guild Enforcer gets +2/+1 and has deathtouch.

Vendilion Clique

Flash
Flying
When Vendilion Clique enters, look at target player's hand. You may choose a nonland card from it. If you do, that player reveals the chosen card, puts it on the bottom of their library, then draws a card.

Alms Collector

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

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 this turn, exile that creature until Hixus leaves the battlefield. (That creature returns under its owner's control.)

Cunning Nightbonder

Flash
Spells with flash you cast cost {1} less to cast and can't be countered.

Mystical Teachings

Search your library for an instant card or a card with flash, reveal it, put it into your hand, then shuffle.
Flashback {5}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Liliana's Standard Bearer

Flash
When Liliana's Standard Bearer enters, draw X cards, where X is the number of creatures that died under your control this turn.

Chromium, the Mutable

Flash
This spell can't be countered.
Flying
Discard a card: Until end of turn, Chromium, the Mutable becomes a Human with base power and toughness 1/1, loses all abilities, and gains hexproof. It can't be blocked this turn.

Stasis Snare

Flash (You may cast this spell any time you could cast an instant.)
When this enchantment enters, exile target creature an opponent controls until this enchantment leaves the battlefield.

Cast Out

Flash
When Cast Out enters, exile target nonland permanent an opponent controls until Cast Out leaves the battlefield.
Cycling {W} ({W}, Discard this card: Draw a card.)

Containment Priest

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

Mizzium Meddler

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

Sea-Dasher Octopus

Mutate {1}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flash
Whenever this creature deals combat damage to a player, draw a card.

Dirge Bat

Mutate {4}{B}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flash
Flying
Whenever this creature mutates, destroy target creature or planeswalker an opponent controls.

Notion Thief

Flash
If an opponent would draw a card except the first one they draw in each of their draw steps, instead that player skips that draw and you draw a card.

Scout's Warning

The next creature card you play this turn can be played as though it had flash.
Draw a card.

Vedalken Orrery

You may cast spells as though they had flash.

Threnody Singer

Flash
Flying
When Threnody Singer enters, target creature an opponent controls gets -X/-0 until end of turn, where X is your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Dream Eater

Flash
Flying
When Dream Eater enters, 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.)

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.

Aven Mindcensor

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

Snapcaster Mage

Flash
When Snapcaster Mage enters, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

Restoration Angel

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

Portal Mage

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

Crookclaw Transmuter

Flash
Flying
When Crookclaw Transmuter enters, switch target creature's power and toughness until end of turn.

Zulaport Duelist

Flash
When Zulaport Duelist enters, up to one target creature gets -2/-0 until end of turn. Its controller mills two cards. (They put the top two cards of their library into their graveyard.)

Slitherwisp

Flash
Whenever you cast another spell that has flash, you draw a card and each opponent loses 1 life.

Faerie Duelist

Flash
Flying
When Faerie Duelist enters, target creature an opponent controls gets -2/-0 until end of turn.

Ashiok's Erasure

Flash
When Ashiok's Erasure enters, exile target spell.
Your opponents can't cast spells with the same name as the exiled card.
When Ashiok's Erasure leaves the battlefield, return the exiled card to its owner's hand.

Dictate of Erebos

Flash
Whenever a creature you control dies, each opponent sacrifices a creature of their choice.

Harbinger of the Tides

You may cast this card as though it had flash if you pay {2} more to cast it. (You may cast it any time you could cast an instant.)
When this creature enters, you may return target tapped creature an opponent controls to its owner's hand.

Blitz Leech

Flash
When Blitz Leech enters, target creature an opponent controls gets -2/-2 until end of turn. Remove all counters from that creature.

Spell Queller

Flash
Flying
When Spell Queller enters, exile target spell with mana value 4 or less.
When Spell Queller leaves the battlefield, the exiled card's owner may cast that card without paying its mana cost.

Petty Theft

Return target nonland permanent an opponent controls to its owner's hand.

Brazen Borrower

Flash
Flying
Brazen Borrower can block only creatures with flying.

Brazen Borrower // Petty Theft

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 this creature.

Quicken

The next sorcery spell you cast this turn can be cast as though it had flash. (It can be cast any time you could cast an instant.)
Draw a card.

Lochmere Serpent

Flash
{U}, Sacrifice an Island: Lochmere Serpent can't be blocked this turn.
{B}, Sacrifice a Swamp: You gain 1 life and draw a card.
{U}{B}: Exile five target cards from an opponent's graveyard. Return Lochmere Serpent from your graveyard to your hand. Activate only as a sorcery.