Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

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.

Counterspell

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Wavebreak Hippocamp

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

Plains

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.)

Snapcaster Mage

Flash
When Snapcaster Mage enters the battlefield, 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.)

Naiad of Hidden Coves

As long as it's not your turn, spells you cast cost {1} less to cast.

Voracious Greatshark

Flash
When Voracious Greatshark enters the battlefield, counter target artifact or creature spell.

Aboleth Spawn

Flash
Ward {2}
Probing Telepathy — Whenever a creature entering the battlefield under an opponent's control causes a triggered ability of that creature to trigger, you may copy that ability. You may choose new targets for the copy.

Terramorphic Expanse

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

Elminster

Whenever you scry, the next instant or sorcery spell you cast this turn costs {X} less to cast, where X is the number of cards looked at while scrying this way.
+2: Draw a card, then scry 2.
−3: Exile the top card of your library. Create a number of 1/1 blue Faerie Dragon creature tokens with flying equal to that card's mana value.
Elminster can be your commander.

Guardian of Faith

Flash
Vigilance
When Guardian of Faith enters the battlefield, any number of other target creatures you control phase out. (Treat them and anything attached to them as though they don't exist until their controller's next turn.)

Swift Reconfiguration

Flash
Enchant creature or Vehicle
Enchanted permanent is a Vehicle artifact with crew 5 and it loses all other card types. (It's not a creature unless it's crewed.)

Nimbus Maze

{T}: Add {C}.
{T}: Add {W}. Activate only if you control an Island.
{T}: Add {U}. Activate only if you control a Plains.

Preordain

Scry 2, then draw a card. (To 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.)

Grey Knight Paragon

Flash
Rites of Banishment — When Grey Knight Paragon enters the battlefield, destroy target attacking creature. If that creature is a Demon, exile it instead.

Githzerai Monk

Flash
Flying
Psychic Defense — When Githzerai Monk enters the battlefield, tap all creatures you don't control.

Errant and Giada

Flash
Flying
You may look at the top card of your library any time.
You may cast spells with flash or flying from the top of your library.

Emergence Zone

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

Containment Priest

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

Command Tower

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

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.)

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.

Stunt Double

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

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Negate

Torrential Gearhulk

Flash
When Torrential Gearhulk enters the battlefield, 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.

Ophidian Eye

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Ghostly Prison

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Windshaper Planetar

Flash
Flying
When Windshaper Planetar enters the battlefield during the declare attackers step, for each attacking creature, you may reselect which player or permanent that creature is attacking. (It can't attack its controller or their permanents.)

Timely Ward

You may cast Timely Ward as though it had flash if it targets a commander.
Enchant creature
Enchanted creature has indestructible.

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.

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.

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}.

Prairie Stream

({T}: Add {W} or {U}.)
Prairie Stream enters the battlefield tapped unless you control two or more basic lands.

Time Wipe

Return a creature you control to its owner's hand, then destroy all creatures.

Vega, the Watcher

Flying
Whenever you cast a spell from anywhere other than your hand, draw a card.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

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.

Merfolk Trickster

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

Archivist of Oghma

Flash
Whenever an opponent searches their library, you gain 1 life and draw a card.

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.

Winged Words

This spell costs {1} less to cast if you control a creature with flying.
Draw two cards.

Dovin's Veto

This spell can't be countered.
Counter target noncreature spell.

Disenchant

Supreme Verdict

This spell can't be countered.
Destroy all creatures.

Prismatic Strands

Prevent all damage that sources of the color of your choice would deal this turn.
Flashback—Tap an untapped white creature you control. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Port Town

As Port Town enters the battlefield, you may reveal a Plains or Island card from your hand. If you don't, Port Town enters the battlefield tapped.
{T}: Add {W} or {U}.

Seht's Tiger

Flash (You may cast this spell any time you could cast an instant.)
When Seht's Tiger enters the battlefield, you gain protection from the color of your choice until end of turn. (You can't be targeted, dealt damage, or enchanted by anything of the chosen color.)

Aven Mindcensor

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

Masako the Humorless

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

Mystic Sanctuary

({T}: Add {U}.)
Mystic Sanctuary enters the battlefield tapped unless you control three or more other Islands.
When Mystic Sanctuary enters the battlefield untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Benevolent Blessing

Flash
Enchant creature
As Benevolent Blessing enters the battlefield, choose a color.
Enchanted creature has protection from the chosen color. This effect doesn't remove Auras and Equipment you control that are already attached to it.

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.

Tamiyo's Compleation

Flash
Enchant artifact, creature, or planeswalker
When Tamiyo's Compleation enters the battlefield, tap enchanted permanent. If it's an Equipment, unattach it.
Enchanted permanent loses all abilities and doesn't untap during its controller's untap step.

As Foretold

At the beginning of your upkeep, put a time counter on As Foretold.
Once each turn, you may pay {0} rather than pay the mana cost for a spell you cast with mana value X or less, where X is the number of time counters on As Foretold.

Sol Ring

Grand Arbiter Augustin IV

White spells you cast cost {1} less to cast.
Blue spells you cast cost {1} less to cast.
Spells your opponents cast cost {1} more to cast.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

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.

Spell Queller

Flash
Flying
When Spell Queller enters the battlefield, 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.

Approach of the Second Sun

If this spell was cast from your hand and you've cast another spell named Approach of the Second Sun this game, you win the game. Otherwise, put Approach of the Second Sun into its owner's library seventh from the top and you gain 7 life.

Mocking Doppelganger

Flash
You may have Mocking Doppelganger enter the battlefield as a copy of a creature an opponent controls, except it has "Other creatures with the same name as this creature are goaded." (They attack each combat if able and attack a player other than you if able.)

Capture Sphere

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
When Capture Sphere enters the battlefield, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Selfless Squire

Flash
When Selfless Squire enters the battlefield, prevent all damage that would be dealt to you this turn.
Whenever damage that would be dealt to you is prevented, put that many +1/+1 counters on Selfless Squire.

Misleading Signpost

Flash
When Misleading Signpost 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 their permanents.)
{T}: Add {U}.

Temple of Enlightenment

Temple of Enlightenment enters the battlefield tapped.
When Temple of Enlightenment enters the battlefield, scry 1.
{T}: Add {W} or {U}.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

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}.

The Wandering Emperor

Flash
As long as The Wandering Emperor entered the battlefield this turn, you may activate her loyalty abilities any time you could cast an instant.
+1: Put a +1/+1 counter on up to one target creature. It gains first strike until end of turn.
−1: Create a 2/2 white Samurai creature token with vigilance.
−2: Exile target tapped creature. You gain 2 life.

Lawmage's Binding

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

Hullbreaker Horror

Flash
This spell can't be countered.
Whenever you cast a spell, choose up to one —
• Return target spell you don't control to its owner's hand.
• Return target nonland permanent to its owner's hand.

Spectral Adversary

Flash
Flying
When Spectral Adversary enters the battlefield, you may pay {1}{U} any number of times. When you pay this cost one or more times, put that many +1/+1 counters on Spectral Adversary, then up to that many other target artifacts, creatures, and/or enchantments phase out.

Arcane Signet

Cathar Commando

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

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.

Midnight Clock

{T}: Add {U}.
{2}{U}: Put an hour counter on Midnight Clock.
At the beginning of each upkeep, put an hour counter on Midnight Clock.
When the twelfth hour counter is put on Midnight Clock, shuffle your hand and graveyard into your library, then draw seven cards. Exile Midnight Clock.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Island

Mithril Coat

Flash
Indestructible
When Mithril Coat enters the battlefield, attach it to target legendary creature you control.
Equipped creature has indestructible.
Equip {3}

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.

Venser, Shaper Savant

Flash
When Venser, Shaper Savant enters the battlefield, return target spell or permanent to its owner's hand.