Rashmi, Eternities Crafter

Whenever you cast your first spell each turn, reveal the top card of your library. You may cast it without paying its mana cost if it's a spell with lesser mana value. If you don't cast it, put it into your hand.

Harbinger of the Tides

You may cast Harbinger of the Tides 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 Harbinger of the Tides enters the battlefield, you may return target tapped creature an opponent controls to its owner's hand.

Pearl Lake Ancient

Flash
This spell can't be countered.
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Return three lands you control to their owner's hand: Return Pearl Lake Ancient to its owner's hand.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Faerie Tauntings

Whenever you cast a spell during an opponent's turn, you may have each opponent lose 1 life.

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.

Whisper Agent

Flash
When Whisper Agent enters the battlefield, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Kheru Spellsnatcher

Morph {4}{U}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Kheru Spellsnatcher is turned face up, counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard. You may cast that card without paying its mana cost for as long as it remains exiled.

Pestermite

Flash
Flying
When Pestermite enters the battlefield, you may tap or untap target permanent.

Omen of the Sea

Flash
When Omen of the Sea enters the battlefield, scry 2, then draw a card.
{2}{U}, Sacrifice Omen of the Sea: Scry 2.

Fleetfeather Cockatrice

Flash (You may cast this spell any time you could cast an instant.)
Flying, deathtouch
{5}{G}{U}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)

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.

Seedborn Muse

Untap all permanents you control during each other player's untap step.

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.)

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.

Thousand Winds

Flying
Morph {5}{U}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Thousand Winds is turned face up, return all other tapped creatures to their owners' hands.

Faerie Vandal

Flash
Flying
Whenever you draw your second card each turn, put a +1/+1 counter on Faerie Vandal.

Simic Sky Swallower

Flying, trample
Shroud (This creature can't be the target of spells or abilities.)

Yarok, the Desecrated

Deathtouch, lifelink
If a permanent entering the battlefield causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

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.

Frilled Mystic

Flash
When Frilled Mystic enters the battlefield, you may counter target spell.

Kefnet's Monument

Blue creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, target creature an opponent controls doesn't untap during its controller's next untap step.

Emergence Zone

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

Myriad Landscape

Myriad Landscape enters the battlefield tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Swamp

Ambush Viper

Darksteel Sentinel

Flash (You may cast this spell any time you could cast an instant.)
Vigilance
Indestructible (Damage and effects that say "destroy" don't destroy this creature. If its toughness is 0 or less, it's still put into its owner's graveyard.)

Dreamspoiler Witches

Flying
Whenever you cast a spell during an opponent's turn, you may have target creature get -1/-1 until end of turn.

Sentinels of Glen Elendra

Island

Bonds of Quicksilver

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature doesn't untap during its controller's untap step.

Terramorphic Expanse

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

Wavebreak Hippocamp

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

Faerie Invaders

Flash (You may cast this spell any time you could cast an instant.)
Flying

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.)

Alchemist's Refuge

{T}: Add {C}.
{G}{U}, {T}: You may cast spells this turn as though they had flash.

Vile Redeemer

Devoid (This card has no color.)
Flash
When you cast this spell, you may pay {C}. If you do, create a 1/1 colorless Eldrazi Scion creature token for each nontoken creature that died under your control this turn. Those tokens have "Sacrifice this creature: Add {C}."

Dictate of Karametra

Flash
Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

Sol Ring

Biomass Mutation

Creatures you control have base power and toughness X/X until end of turn.

Kadena's Silencer

When Kadena's Silencer is turned face up, counter all abilities your opponents control.
Megamorph {1}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)

Undersea Invader

Flash
Undersea Invader enters the battlefield tapped.

Savage Summoning

This spell can't be countered.
The next creature spell you cast this turn can be cast as though it had flash. That spell can't be countered. That creature enters the battlefield with an additional +1/+1 counter on it.

Riddlemaster Sphinx

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Riddlemaster Sphinx enters the battlefield, you may return target creature an opponent controls to its owner's hand.

Vernal Equinox

Any player may cast creature and enchantment spells as though they had flash.

Spellstutter Sprite

Flash
Flying
When Spellstutter Sprite enters the battlefield, counter target spell with mana value X or less, where X is the number of Faeries you control.

Dictate of Kruphix

Flash
At the beginning of each player's draw step, that player draws an additional card.

Dragon Turtle

Flash
Drag Below — When Dragon Turtle enters the battlefield, tap it and up to one target creature an opponent controls. They don't untap during their controllers' next untap steps.

Nymris, Oona's Trickster

Flash
Flying
Whenever you cast your first spell during each opponent's turn, look at the top two cards of your library. Put one of those cards into your hand and the other into your graveyard.

Bounty of the Luxa

At the beginning of your precombat main phase, remove all flood counters from Bounty of the Luxa. If no counters were removed this way, put a flood counter on Bounty of the Luxa and draw a card. Otherwise, add {C}{G}{U}.

Evolving Wilds

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

Glen Elendra Pranksters

Flying
Whenever you cast a spell during an opponent's turn, you may return target creature you control to its owner's hand.

Faerie Harbinger

Flash
Flying
When Faerie Harbinger enters the battlefield, you may search your library for a Faerie card, reveal it, then shuffle and put that card on top.

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.

Stinging Lionfish

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

Dire Mimic

Flash
{T}, Sacrifice Dire Mimic: Add one mana of any color.
{3}: Dire Mimic becomes a Shapeshifter artifact creature with base power and toughness 5/5 until end of turn.

Sudden Substitution

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Exchange control of target noncreature spell and target creature. Then the spell's controller may choose new targets for it.

Thought Sponge

Flash
Thought Sponge enters the battlefield with a number of +1/+1 counters on it equal to the greatest number of cards an opponent has drawn this turn.
When Thought Sponge dies, draw cards equal to its power.

Stolen by the Fae

Return target creature with mana value X to its owner's hand. You create X 1/1 blue Faerie creature tokens with flying.

Tidal Barracuda

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

Vivien, Champion of the Wilds

You may cast creature spells as though they had flash.
+1: Until your next turn, up to one target creature gains vigilance and reach.
−2: Look at the top three cards of your library. Exile one face down and put the rest on the bottom of your library in any order. For as long as it remains exiled, you may look at that card and you may cast it if it's a creature spell.

Vedalken Orrery

You may cast spells as though they had flash.

Forest

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.

Wydwen, the Biting Gale

Flash
Flying
{U}{B}, Pay 1 life: Return Wydwen, the Biting Gale to its owner's hand.

Cunning Nightbonder

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

Yeva, Nature's Herald

Flash (You may cast this spell any time you could cast an instant.)
You may cast green creature spells as though they had flash.