Polymorphist's Jest

Until end of turn, each creature target player controls loses all abilities and becomes a blue Frog with base power and toughness 1/1.

Niv-Mizzet, the Firemind

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

Guile

Guile can't be blocked except by three or more creatures.
If a spell or ability you control would counter a spell, instead exile that spell and you may play that card without paying its mana cost.
When Guile is put into a graveyard from anywhere, shuffle it into its owner's library.

Consign to Dream

Return target permanent to its owner's hand. If that permanent is red or green, put it on top of its owner's library instead.

Chromatic Orrery

You may spend mana as though it were mana of any color.
{T}: Add {C}{C}{C}{C}{C}.
{5}, {T}: Draw a card for each color among permanents you control.

Sudden Demise

Choose a color. Sudden Demise deals X damage to each creature of the chosen color.

Crimson Wisps

Target creature becomes red and gains haste until end of turn.
Draw a card.

Sway of Illusion

Any number of target creatures become the color of your choice until end of turn.
Draw a card.

Ugin's Nexus

If a player would begin an extra turn, that player skips that turn instead.
If Ugin's Nexus would be put into a graveyard from the battlefield, instead exile it and take an extra turn after this one.

Painter's Servant

As Painter's Servant enters, choose a color.
All cards that aren't on the battlefield, spells, and permanents are the chosen color in addition to their other colors.

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Scuttlemutt

{T}: Add one mana of any color.
{T}: Target creature becomes the color or colors of your choice until end of turn.

Containment Construct

Whenever you discard a card, you may exile that card from your graveyard. If you do, you may play that card this turn.

Blue Elemental Blast

Choose one —
• Counter target red spell.
• Destroy target red permanent.

Aether Gust

Choose target spell or permanent that's red or green. Its owner puts it on the top or bottom of their library.

This spell can't be countered.
Fry deals 5 damage to target creature or planeswalker that's white or blue.

Douse

Willbreaker

Whenever a creature an opponent controls becomes the target of a spell or ability you control, gain control of that creature for as long as you control Willbreaker.

Battlemage's Bracers

Equipped creature has haste.
Whenever an ability of equipped creature is activated, if it isn't a mana ability, you may pay {1}. If you do, copy that ability. You may choose new targets for the copy.
Equip {2}

Fevered Visions

At the beginning of each player's end step, that player draws a card. If the player is your opponent and has four or more cards in hand, Fevered Visions deals 2 damage to that player.

Lithoform Engine

{2}, {T}: Copy target activated or triggered ability you control. You may choose new targets for the copy.
{3}, {T}: Copy target instant or sorcery spell you control. You may choose new targets for the copy.
{4}, {T}: Copy target permanent spell you control. (The copy becomes a token.)

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.

Fractured Loyalty

Enchant creature
Whenever enchanted creature becomes the target of a spell or ability, that spell or ability's controller gains control of that creature. (This effect lasts indefinitely.)

Unquenchable Fury

Enchant creature
Enchanted creature has "Whenever this creature attacks, it deals X damage to defending player, where X is the number of cards in their hand."
When Unquenchable Fury is put into your graveyard from the battlefield, return it to your hand.

Sulfur Elemental

Flash
Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
White creatures get +1/-1.

Firemind's Foresight

Search your library for an instant card with mana value 3, reveal it, and put it into your hand. Then repeat this process for instant cards with mana values 2 and 1. Then shuffle.

Scion of Draco

Domain — This spell costs {2} less to cast for each basic land type among lands you control.
Flying
Each creature you control has vigilance if it's white, hexproof if it's blue, lifelink if it's black, first strike if it's red, and trample if it's green.

Cerulean Wisps

Target creature becomes blue until end of turn. Untap that creature.
Draw a card.

Sword of War and Peace

Equipped creature gets +2/+2 and has protection from red and from white.
Whenever equipped creature deals combat damage to a player, Sword of War and Peace deals damage to that player equal to the number of cards in their hand and you gain 1 life for each card in your hand.
Equip {2}

Well-Laid Plans

Prevent all damage that would be dealt to a creature by another creature if they share a color.

Llawan, Cephalid Empress

When Llawan, Cephalid Empress enters, return all blue creatures your opponents control to their owners' hands.
Your opponents can't cast blue creature spells.

Grand Architect

Other blue creatures you control get +1/+1.
{U}: Target artifact creature becomes blue until end of turn.
Tap an untapped blue creature you control: Add {C}{C}. Spend this mana only to cast artifact spells or activate abilities of artifacts.

Illusionist's Bracers

Whenever an ability of equipped creature is activated, if it isn't a mana ability, copy that ability. You may choose new targets for the copy.
Equip {3}

Soul of Ravnica

Flying
{5}{U}{U}: Draw a card for each color among permanents you control.
{5}{U}{U}, Exile Soul of Ravnica from your graveyard: Draw a card for each color among permanents you control.

Body of Knowledge

Body of Knowledge's power and toughness are each equal to the number of cards in your hand.
You have no maximum hand size.
Whenever Body of Knowledge is dealt damage, draw that many cards.

Red Elemental Blast

Choose one —
• Counter target blue spell.
• Destroy target blue permanent.

Govern the Guildless

Gain control of target monocolored creature.
Forecast — {1}{U}, Reveal Govern the Guildless from your hand: Target creature becomes the color or colors of your choice until end of turn. (Activate only during your upkeep and only once each turn.)

Breaching Leviathan

When Breaching Leviathan enters, if you cast it from your hand, tap all nonblue creatures. Those creatures don't untap during their controllers' next untap steps.

Sol Ring

Blood Knight

Heartstone

Activated abilities of creatures cost {1} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Inundate

Return all nonblue creatures to their owners' hands.

Hydroblast

Choose one —
• Counter target spell if it's red.
• Destroy target permanent if it's red.

Marang River Prowler

Marang River Prowler can't block and can't be blocked.
You may cast Marang River Prowler from your graveyard as long as you control a black or green permanent.

Embermaw Hellion

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
If another red source you control would deal damage to a permanent or player, it deals that much damage plus 1 to that permanent or player instead.

Dream Halls

Rather than pay the mana cost for a spell, its controller may discard a card that shares a color with that spell.

Niv-Mizzet, Dracogenius

Flying
Whenever Niv-Mizzet, Dracogenius deals damage to a player, you may draw a card.
{U}{R}: Niv-Mizzet, Dracogenius deals 1 damage to any target.

Indigo Faerie

Flying
{U}: Target permanent becomes blue in addition to its other colors until end of turn.

Jaya Ballard, Task Mage

{R}, {T}, Discard a card: Destroy target blue permanent.
{1}{R}, {T}, Discard a card: Jaya Ballard, Task Mage deals 3 damage to any target. A creature dealt damage this way can't be regenerated this turn.
{5}{R}{R}, {T}, Discard a card: Jaya Ballard deals 6 damage to each creature and each player.

Hibernation

Return all green permanents to their owners' hands.

Dismiss into Dream

Each creature your opponents control is an Illusion in addition to its other types and has "When this creature becomes the target of a spell or ability, sacrifice it."

Blind Seer

{1}{U}: Target spell or permanent becomes the color of your choice until end of turn.

Sanctuary Blade

As Sanctuary Blade becomes attached to a creature, choose a color.
Equipped creature gets +2/+0 and has protection from the last chosen color.
Equip {3}

Burning Hands

Burning Hands deals 2 damage to target creature or planeswalker. If that permanent is green, Burning Hands deals 6 damage instead.

Jaded Response

Counter target spell if it shares a color with a creature you control.

Training Grounds

Activated abilities of creatures you control cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.