Chrome Host Seedshark

Flying
Whenever you cast a noncreature spell, incubate X, where X is that spell's mana value. (Create an Incubator token with X +1/+1 counters on it and "{2}: Transform this token." It transforms into a 0/0 Phyrexian artifact creature.)

Young Pyromancer

Whenever you cast an instant or sorcery spell, create a 1/1 red Elemental creature token.

Flashback

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.)

Wild Idea

Search your library for an instant or sorcery card, reveal it, put it into your hand, then shuffle.

Sanar, Unfinished Genius

Sanar enters prepared. (While it's prepared, you may cast a copy of its spell. Doing so unprepares it.)
{T}: Create a Treasure token. Activate only if you've cast an instant or sorcery spell this turn.

Sanar, Unfinished Genius // Wild Idea

Rapturous Moment

Draw three cards, then discard two cards. Add {U}{U}{R}{R}{R}.

Mathemagics

Target player draws 2ˣ cards. (2º = 1, 2¹ = 2, 2² = 4, 2³ = 8, 2⁴ = 16, 2⁵ = 32, and so on.)

Quick Study

Desperate Ritual

Add {R}{R}{R}.
Splice onto Arcane {1}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Ashling's Command

Choose two —
• Create a token that's a copy of target Elemental you control.
• Target player draws two cards.
• Ashling's Command deals 2 damage to each creature target player controls.
• Target player creates two Treasure tokens.

Overpowering Attack

Freerunning {2}{R} (You may cast this spell for its freerunning cost if you dealt combat damage to a player this turn with an Assassin or commander.)
Untap all creatures you control that attacked this turn. If it's your main phase, there is an additional combat phase after this phase, followed by an additional main phase.

Great Train Heist

Spree (Choose one or more additional costs.)
+ {2}{R} — Untap all creatures you control. If it's your combat phase, there is an additional combat phase after this phase.
+ {2} — Creatures you control get +1/+0 and gain first strike until end of turn.
+ {R} — Choose target opponent. Whenever a creature you control deals combat damage to that player this turn, create a tapped Treasure token.

Rootha, Mastering the Moment

At the beginning of combat on your turn, if you've cast an instant or sorcery spell this turn, create an X/X blue and red Elemental creature token with flying and haste, where X is the greatest mana value among instant and sorcery spells you've cast this turn.

Electro, Assaulting Battery

Flying
You don't lose unspent red mana as steps and phases end.
Whenever you cast an instant or sorcery spell, add {R}.
When Electro leaves the battlefield, you may pay {X}. When you do, he deals X damage to target player.

Full Throttle

After this main phase, there are two additional combat phases.
At the beginning of each combat this turn, untap all creatures that attacked this turn.

Electrodominance

Electrodominance deals X damage to any target. You may cast a spell with mana value X or less from your hand without paying its mana cost.

Mana Sculpt

Counter target spell. If you control a Wizard, add an amount of {C} equal to the amount of mana spent to cast that spell at the beginning of your next main phase.

Muse Seeker

Opus — Whenever you cast an instant or sorcery spell, draw a card. Then discard a card unless five or more mana was spent to cast that spell.

Mystic Peak

As this land enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {R}.

Pinnacle Monk

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When this creature enters, return target instant or sorcery card from your graveyard to your hand.

Pinnacle Monk // Mystic Peak

Abstract Paintmage

At the beginning of your first main phase, add {U}{R}. Spend this mana only to cast instant and sorcery spells.

Part the Waterveil

Take an extra turn after this one. Exile Part the Waterveil.
Awaken 6—{6}{U}{U}{U} (If you cast this spell for {6}{U}{U}{U}, also put six +1/+1 counters on target land you control and it becomes a 0/0 Elemental creature with haste. It's still a land.)

Commandeer

You may exile two blue cards from your hand rather than pay this spell's mana cost.
Gain control of target noncreature spell. You may choose new targets for it. (If that spell is an artifact, enchantment, or planeswalker, the permanent enters under your control.)

Spectacle Mage

Flying
Instant and sorcery spells you cast with mana value 5 or greater cost {1} less to cast.

Ashling, Rimebound

Whenever this creature transforms into Ashling, Rimebound and at the beginning of your first main phase, add two mana of any one color. Spend this mana only to cast spells with mana value 4 or greater.
At the beginning of your first main phase, you may pay {R}. If you do, transform Ashling.

Ashling, Rekindled

Whenever this creature enters or transforms into Ashling, Rekindled, you may discard a card. If you do, draw a card.
At the beginning of your first main phase, you may pay {U}. If you do, transform Ashling.

Ashling, Rekindled // Ashling, Rimebound

Thunderdrum Soloist

Reach
Opus — Whenever you cast an instant or sorcery spell, this creature deals 1 damage to each opponent. If five or more mana was spent to cast that spell, this creature deals 3 damage to each opponent instead.

Brainstorm

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

Harmonized Trio

{T}, Tap two untapped creatures you control: This creature becomes prepared. (While it's prepared, you may cast a copy of its spell. Doing so unprepares it.)

Harmonized Trio // Brainstorm

Relentless Assault

Untap all creatures that attacked this turn. After this main phase, there is an additional combat phase followed by an additional main phase.

Savage Beating

Cast this spell only during combat on your turn.
Choose one —
• Creatures you control gain double strike until end of turn.
• Untap all creatures you control. After this phase, there is an additional combat phase.
Entwine {1}{R} (Choose both if you pay the entwine cost.)

Hydro-Channeler

{T}: Add {U}. Spend this mana only to cast an instant or sorcery spell.
{1}, {T}: Add one mana of any color. Spend this mana only to cast an instant or sorcery spell.

Fractal Anomaly

Create a 0/0 green and blue Fractal creature token and put X +1/+1 counters on it, where X is the number of cards you've drawn this turn.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Emeritus of Conflict

First strike
Whenever you cast your third spell each turn, this creature becomes prepared. (While it's prepared, you may cast a copy of its spell. Doing so unprepares it.)

Emeritus of Conflict // Lightning Bolt

Diary of Dreams

Whenever you cast an instant or sorcery spell, put a page counter on this artifact.
{5}, {T}: Draw a card. This ability costs {1} less to activate for each page counter on this artifact.

Frantic Search

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

Karn's Temporal Sundering

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Target player takes an extra turn after this one. Return up to one target nonland permanent to its owner's hand. Exile Karn's Temporal Sundering.

Ghired's Belligerence

Ghired's Belligerence deals X damage divided as you choose among any number of target creatures. Whenever a creature dealt damage this way dies this turn, populate. (Create a token that's a copy of a creature token you control.)

Fury of the Horde

You may exile two red cards from your hand rather than pay this spell's mana cost.
Untap all creatures that attacked this turn. After this main phase, there is an additional combat phase followed by an additional main phase.

Talrand, Sky Summoner

Whenever you cast an instant or sorcery spell, create a 2/2 blue Drake creature token with flying.

Molten-Core Maestro

Menace
Opus — Whenever you cast an instant or sorcery spell, put a +1/+1 counter on this creature. If five or more mana was spent to cast that spell, add an amount of {R} equal to this creature's power.

Alrund's Epiphany

Create two 1/1 blue Bird creature tokens with flying. Take an extra turn after this one. Exile Alrund's Epiphany.
Foretell {4}{U}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Perplexing Test

Choose one —
• Return all creature tokens to their owners' hands.
• Return all nontoken creatures to their owners' hands.

Seize the Day

Untap target creature. After this main phase, there is an additional combat phase followed by an additional main phase.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Craft with Pride

Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Goblin Glasswright

This creature enters prepared. (While it's prepared, you may cast a copy of its spell. Doing so unprepares it.)

Goblin Glasswright // Craft with Pride

Traumatic Critique

Traumatic Critique deals X damage to any target. Draw two cards, then discard a card.

Visionary's Dance

Create two 3/3 blue and red Elemental creature tokens with flying.
{2}, Discard this card: Look at the top two cards of your library. Put one of them into your hand and the other into your graveyard.

Inspired Tinkering

Exile the top three cards of your library. Until the end of your next turn, you may play those cards.
Create three Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Archmage of Runes

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

Fact or Fiction

Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Balmor, Battlemage Captain

Flying
Whenever you cast an instant or sorcery spell, creatures you control get +1/+0 and gain trample until end of turn.

Haughty Djinn

Flying
Haughty Djinn's power is equal to the number of instant and sorcery cards in your graveyard.
Instant and sorcery spells you cast cost {1} less to cast.

World at War

After the second main phase this turn, there's an additional combat phase followed by an additional main phase. At the beginning of that combat, untap all creatures that attacked this turn.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Resonating Lute

Lands you control have "{T}: Add two mana of any one color. Spend this mana only to cast instant and sorcery spells."
{T}: Draw a card. Activate only if you have seven or more cards in your hand.

Great Hall of the Biblioplex

{T}: Add {C}.
{T}, Pay 1 life: Add one mana of any color. Spend this mana only to cast an instant or sorcery spell.
{5}: If this land isn't a creature, it becomes a 2/4 Wizard creature with "Whenever you cast an instant or sorcery spell, this creature gets +1/+0 until end of turn." It's still a land.