Toothy, Imaginary Friend

Partner with Pir, Imaginative Rascal (When this creature enters, target player may put Pir into their hand from their library, then shuffle.)
Whenever you draw a card, put a +1/+1 counter on Toothy, Imaginary Friend.
When Toothy leaves the battlefield, draw a card for each +1/+1 counter on it.

Jaya Ballard

+1: Add {R}{R}{R}. Spend this mana only to cast instant or sorcery spells.
+1: Discard up to three cards, then draw that many cards.
−8: You get an emblem with "You may cast instant and sorcery spells from your graveyard. If a spell cast this way would be put into your graveyard, exile it instead."

Izzet Charm

Choose one —
• Counter target noncreature spell unless its controller pays {2}.
• Izzet Charm deals 2 damage to target creature.
• Draw two cards, then discard two cards.

Rielle, the Everwise

Rielle, the Everwise gets +1/+0 for each instant and sorcery card in your graveyard.
Whenever you discard one or more cards for the first time each turn, draw that many cards.

Rites of Refusal

Discard any number of cards. Counter target spell unless its controller pays {3} for each card discarded this way.

Underworld Breach

Each nonland card in your graveyard has escape. The escape cost is equal to the card's mana cost plus exile three other cards from your graveyard. (You may cast cards from your graveyard for their escape cost.)
At the beginning of the end step, sacrifice Underworld Breach.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Mind Over Matter

Discard a card: You may tap or untap target artifact, creature, or land.

Breakthrough

Draw four cards, then choose X cards in your hand and discard the rest.

Tolarian Winds

Discard all the cards in your hand, then draw that many cards.

Arcane Signet

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

Channeled Force

As an additional cost to cast this spell, discard X cards.
Target player draws X cards. Channeled Force deals X damage to up to one target creature or planeswalker.

Thrill of Possibility

As an additional cost to cast this spell, discard a card.
Draw two cards.

Island

Fateful Showdown

Fateful Showdown deals damage to any target equal to the number of cards in your hand. Discard all the cards in your hand, then draw that many cards.

Izzet Boilerworks

Izzet Boilerworks enters tapped.
When Izzet Boilerworks enters, return a land you control to its owner's hand.
{T}: Add {U}{R}.

Goblin Electromancer

Instant and sorcery spells you cast cost {1} less to cast.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Cephalid Coliseum

{T}: Add {U}. Cephalid Coliseum deals 1 damage to you.
Threshold — {U}, {T}, Sacrifice Cephalid Coliseum: Target player draws three cards, then discards three cards. Activate only if seven or more cards are in your graveyard.

Chasm Skulker

Whenever you draw a card, put a +1/+1 counter on Chasm Skulker.
When Chasm Skulker dies, create X 1/1 blue Squid creature tokens with islandwalk, where X is the number of +1/+1 counters on Chasm Skulker. (They can't be blocked as long as defending player controls an Island.)

Dack Fayden

+1: Target player draws two cards, then discards two cards.
−2: Gain control of target artifact.
−6: You get an emblem with "Whenever you cast a spell that targets one or more permanents, gain control of those permanents."

Ominous Seas

Whenever you draw a card, put a foreshadow counter on Ominous Seas.
Remove eight foreshadow counters from Ominous Seas: Create an 8/8 blue Kraken creature token.
Cycling {2} ({2}, Discard this card: Draw a card.)

Forbid

Buyback—Discard two cards. (You may discard two cards in addition to any other costs as you cast this spell. If you do, put this card into your hand as it resolves.)
Counter target spell.

Cathartic Reunion

As an additional cost to cast this spell, discard two cards.
Draw three cards.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

The Locust God

Flying
Whenever you draw a card, create a 1/1 blue and red Insect creature token with flying and haste.
{2}{U}{R}: Draw a card, then discard a card.
When The Locust God dies, return it to its owner's hand at the beginning of the next end step.

Cascade Bluffs

{T}: Add {C}.
{U/R}, {T}: Add {U}{U}, {U}{R}, or {R}{R}.

Psychosis Crawler

Psychosis Crawler's power and toughness are each equal to the number of cards in your hand.
Whenever you draw a card, each opponent loses 1 life.

Fiery Islet

{T}, Pay 1 life: Add {U} or {R}.
{1}, {T}, Sacrifice Fiery Islet: Draw a card.

Talisman of Creativity

{T}: Add {C}.
{T}: Add {U} or {R}. Talisman of Creativity deals 1 damage to you.

Niv-Mizzet, the Firemind

Flying
Whenever you draw a card, Niv-Mizzet, the Firemind deals 1 damage to any target.
{T}: Draw a card.

Psychic Corrosion

Whenever you draw a card, each opponent mills two cards.

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Kozilek, the Great Distortion

When you cast this spell, if you have fewer than seven cards in hand, draw cards equal to the difference.
Menace
Discard a card with mana value X: Counter target spell with mana value X.

Hisoka, Minamo Sensei

{2}{U}, Discard a card: Counter target spell if it has the same mana value as the discarded card.

Thought Vessel

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

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Forgotten Cave

Forgotten Cave enters tapped.
{T}: Add {R}.
Cycling {R} ({R}, Discard this card: Draw a card.)

Sulfur Falls

Sulfur Falls enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Thassa's Oracle

When Thassa's Oracle enters, look at the top X cards of your library, where X is your devotion to blue. Put up to one of them on top of your library and the rest on the bottom of your library in a random order. If X is greater than or equal to the number of cards in your library, you win the game. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Careful Study

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Library of Leng

You have no maximum hand size.
If an effect causes you to discard a card, discard it, but you may put it on top of your library instead of into your graveyard.

Mystic Sanctuary

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

Jace's Archivist

{U}, {T}: Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Ox of Agonas

When Ox of Agonas enters, discard your hand, then draw three cards.
Escape—{R}{R}, Exile eight other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)
Ox of Agonas escapes with a +1/+1 counter on it.

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

Surly Badgersaur

Whenever you discard a creature card, put a +1/+1 counter on Surly Badgersaur.
Whenever you discard a land card, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Whenever you discard a noncreature, nonland card, Surly Badgersaur fights up to one target creature you don't control.

Shivan Reef

{T}: Add {C}.
{T}: Add {U} or {R}. Shivan Reef deals 1 damage to you.

Mana Geyser

Add {R} for each tapped land your opponents control.

Read the Runes

Draw X cards. For each card drawn this way, discard a card unless you sacrifice a permanent.

Turbulent Dreams

As an additional cost to cast this spell, discard X cards.
Return X target nonland permanents to their owners' hands.

Firestorm

As an additional cost to cast this spell, discard X cards.
Firestorm deals X damage to each of X targets.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Niv-Mizzet, Parun

This spell can't be countered.
Flying
Whenever you draw a card, Niv-Mizzet, Parun deals 1 damage to any target.
Whenever a player casts an instant or sorcery spell, you draw a card.

Forgotten Creation

Skulk (This creature can't be blocked by creatures with greater power.)
At the beginning of your upkeep, you may discard all the cards in your hand. If you do, draw that many cards.

Dangerous Wager

Sphinx's Tutelage

Whenever you draw a card, target opponent mills two cards. If two nonland cards that share a color were milled this way, repeat this process.
{5}{U}: Draw a card, then discard a card.

Izzet Signet

Jace's Sanctum

Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell, scry 1.

Desolate Lighthouse

{T}: Add {C}.
{1}{U}{R}, {T}: Draw a card, then discard a card.

Command Tower

Chandra, Flamecaller

+1: Create two 3/1 red Elemental creature tokens with haste. Exile them at the beginning of the next end step.
0: Discard all the cards in your hand, then draw that many cards plus one.
−X: Chandra, Flamecaller deals X damage to each creature.

Rites of Initiation

Discard any number of cards at random. Creatures you control get +1/+0 until end of turn for each card discarded this way.

Geier Reach Sanitarium

{T}: Add {C}.
{2}, {T}: Each player draws a card, then discards a card.

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Mountain

Jace, Wielder of Mysteries

If you would draw a card while your library has no cards in it, you win the game instead.
+1: Target player mills two cards. Draw a card.
−8: Draw seven cards. Then if your library has no cards in it, you win the game.

Narset, Parter of Veils

Each opponent can't draw more than one card each turn.
−2: Look at the top four cards of your library. You may reveal a noncreature, nonland card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Mystic Remora

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Reliquary Tower

Foil

You may discard an Island card and another card rather than pay this spell's mana cost.
Counter target spell.

Brallin, Skyshark Rider

Partner with Shabraz, the Skyshark (When this creature enters, target player may put Shabraz into their hand from their library, then shuffle.)
Whenever you discard a card, put a +1/+1 counter on Brallin, Skyshark Rider and it deals 1 damage to each opponent.
{R}: Target Shark gains trample until end of turn.

Laboratory Maniac

If you would draw a card while your library has no cards in it, you win the game instead.

Steam Vents

({T}: Add {U} or {R}.)
As Steam Vents enters, you may pay 2 life. If you don't, it enters tapped.

Magus of the Bazaar

{T}: Draw two cards, then discard three cards.

Sol Ring

Gamble

Search your library for a card, put that card into your hand, discard a card at random, then shuffle.

Temple of Epiphany

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {U} or {R}.

Bag of Holding

Whenever you discard a card, exile that card from your graveyard.
{2}, {T}: Draw a card, then discard a card.
{4}, {T}, Sacrifice Bag of Holding: Return all cards exiled with Bag of Holding to their owner's hand.

Flowstone Flood

Buyback—Pay 3 life, Discard a card at random. (You may pay 3 life and discard a card at random in addition to any other costs as you cast this spell. If you do, put this card into your hand as it resolves.)
Destroy target land.

Lonely Sandbar

Lonely Sandbar enters tapped.
{T}: Add {U}.
Cycling {U} ({U}, Discard this card: Draw a card.)