Day of Black Sun

Each creature with mana value X or less loses all abilities until end of turn. Destroy those creatures.

Unleash Fury

Double the power of target creature until end of turn.

Goblin Electromancer

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

Frantic Search

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

Terramorphic Expanse

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

Demand Answers

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

Ozai, the Phoenix King

Trample, firebending 4, haste
If you would lose unspent mana, that mana becomes red instead.
Ozai has flying and indestructible as long as you have six or more unspent mana.

Redirect Lightning

As an additional cost to cast this spell, pay 5 life or pay {2}.
Change the target of target spell or ability with a single target.

Storm-Kiln Artist

This creature gets +1/+0 for each artifact you control.
Magecraft — Whenever you cast or copy an instant or sorcery spell, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Invoke Calamity

You may cast up to two instant and/or sorcery spells with total mana value 6 or less from your graveyard and/or hand without paying their mana costs. If those spells would be put into your graveyard, exile them instead. Exile Invoke Calamity.

Cunning Maneuver

Target creature gets +3/+1 until end of turn.
Create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Veyran, Voice of Duality

Magecraft — Whenever you cast or copy an instant or sorcery spell, Veyran gets +1/+1 until end of turn.
If you casting or copying an instant or sorcery spell causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Sunken Hollow

({T}: Add {U} or {B}.)
This land enters tapped unless you control two or more basic lands.

Nightscape Familiar

Blue spells and red spells you cast cost {1} less to cast.
{1}{B}: Regenerate this creature.

Fated Firepower

Flash
This enchantment enters with X fire counters on it.
If a source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus an amount of damage equal to the number of fire counters on this enchantment instead.

Fellwar Stone

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

Counterspell

Heartless Act

Choose one —
• Destroy target creature with no counters on it.
• Remove up to three counters from target creature.

Evolving Wilds

Abandon Attachments

You may discard a card. If you do, draw two 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.)

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Fists of Flame

Draw a card. Until end of turn, target creature gains trample and gets +1/+0 for each card you've drawn this turn. (A creature with trample can deal excess combat damage to the player or planeswalker it's attacking.)

Zuko, Firebending Master

First strike
Firebending X, where X is the number of experience counters you have. (Whenever this creature attacks, add X {R}. This mana lasts until end of combat.)
Whenever you cast a spell during combat, you get an experience counter.

Fire Nation Palace

This land enters tapped unless you control a basic land.
{T}: Add {R}.
{1}{R}, {T}: Target creature you control gains firebending 4 until end of turn. (Whenever it attacks, add {R}{R}{R}{R}. This mana lasts until end of combat.)

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.

Comet Storm

Multikicker {1} (You may pay an additional {1} any number of times as you cast this spell.)
Choose any target, then choose another target for each time this spell was kicked. Comet Storm deals X damage to each of them.

Bulk Up

Double target creature's power until end of turn.
Flashback {4}{R}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

How to Start a Riot

Target creature gains menace until end of turn. (It can't be blocked except by two or more creatures.)
Creatures target player controls get +2/+0 until end of turn.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Archmage Emeritus

Magecraft — Whenever you cast or copy an instant or sorcery spell, draw a card.

Guttersnipe

Whenever you cast an instant or sorcery spell, this creature deals 2 damage to each opponent.

Rogue's Passage

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

Azula, Cunning Usurper

Firebending 2 (Whenever this creature attacks, add {R}{R}. This mana lasts until end of combat.)
When Azula enters, target opponent exiles a nontoken creature they control, then they exile a nonland card from their graveyard.
During your turn, you may cast cards exiled with Azula and you may cast them as though they had flash. Mana of any type can be spent to cast those spells.

Sozin's Comet

Each creature you control gains firebending 5 until end of turn. (Whenever it attacks, add {R}{R}{R}{R}{R}. This mana lasts until end of combat.)
Foretell {2}{R} (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.)

Octopus Form

Target creature you control gets +1/+1 and gains hexproof until end of turn. Untap it. (It can't be the target of spells or abilities your opponents control.)

Fire Nation Attacks

Create two 2/2 red Soldier creature tokens with firebending 1. (Whenever a creature with firebending 1 attacks, add {R}. This mana lasts until end of combat.)
Flashback {8}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Sol Ring

Path of Ancestry

This land enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Command Tower

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

High Fae Trickster

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

Azula Always Lies

Choose one or both —
• Target creature gets -1/-1 until end of turn.
• Put a +1/+1 counter on target creature.

Epic Downfall

Exile target creature with mana value 3 or greater.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Bender's Waterskin

Untap this artifact during each other player's untap step.
{T}: Add one mana of any color.

Crumbling Necropolis

This land enters tapped.
{T}: Add {U}, {B}, or {R}.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Negate

Izzet Signet

Sulfur Falls

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

Exotic Orchard

Etali, Primal Storm

Whenever Etali attacks, exile the top card of each player's library, then you may cast any number of spells from among those cards without paying their mana costs.

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.

Zuko, Exiled Prince

Firebending 3 (Whenever this creature attacks, add {R}{R}{R}. This mana lasts until end of combat.)
{3}: Exile the top card of your library. You may play that card this turn.

Dimir Signet

Borne Upon a Wind

You may cast spells this turn as though they had flash.
Draw a card.

Ty Lee, Artful Acrobat

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever Ty Lee attacks, you may pay {1}. When you do, target creature can't block this turn.

The Blue Spirit

You may cast the first creature spell you cast each turn as though it had flash.
Whenever a nontoken creature you control enters during combat, draw a card.

Leyline of Anticipation

If this card is in your opening hand, you may begin the game with it on the battlefield.
You may cast spells as though they had flash.

Brainstorm

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

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

It'll Quench Ya!

Counter target spell unless its controller pays {2}.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Fire Lord Azula

Firebending 2 (Whenever this creature attacks, add {R}{R}. This mana lasts until end of combat.)
Whenever you cast a spell while Fire Lord Azula is attacking, copy that spell. You may choose new targets for the copy. (A copy of a permanent spell becomes a token.)

Narset's Reversal

Copy target instant or sorcery spell, then return it to its owner's hand. You may choose new targets for the copy.

Arcane Signet

Avatar Roku, Firebender

Whenever a player attacks, add six {R}. Until end of combat, you don't lose this mana as steps end.
{R}{R}{R}: Target creature gets +3/+0 until end of turn.

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Stormcatch Mentor

Haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Instant and sorcery spells you cast cost {1} less to cast.

Longshot, Rebel Bowman

Reach (This creature can block creatures with flying.)
Noncreature spells you cast cost {1} less to cast.
Whenever you cast a noncreature spell, Longshot deals 2 damage to each opponent.

Firebending Lesson

Kicker {4} (You may pay an additional {4} as you cast this spell.)
Firebending Lesson deals 2 damage to target creature. If this spell was kicked, it deals 5 damage to that creature instead.

Swamp

Mountain

The Last Agni Kai

Target creature you control fights target creature an opponent controls. If the creature the opponent controls is dealt excess damage this way, add that much {R}.
Until end of turn, you don't lose unspent red mana as steps and phases end.

Firebender Ascension

When this enchantment enters, create a 2/2 red Soldier creature token with firebending 1.
Whenever a creature you control attacking causes a triggered ability of that creature to trigger, put a quest counter on this enchantment. Then if it has four or more quest counters on it, you may copy that ability. You may choose new targets for the copy.

Island

Smoldering Marsh

({T}: Add {B} or {R}.)
This land enters tapped unless you control two or more basic lands.

Big Score

As an additional cost to cast this spell, discard a card.
Draw two cards and create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Firebending Student

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Firebending X, where X is this creature's power. (Whenever this creature attacks, add X {R}. This mana lasts until end of combat.)

Shivan Reef

{T}: Add {C}.
{T}: Add {U} or {R}. This land deals 1 damage to you.

Dragonskull Summit

This land enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Ty Lee, Chi Blocker

Flash
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Ty Lee enters, tap up to one target creature. It doesn't untap during its controller's untap step for as long as you control Ty Lee.

Thousand-Year Storm

Whenever you cast an instant or sorcery spell, copy it for each other instant and sorcery spell you've cast before it this turn. You may choose new targets for the copies.