April O'Neil, Human Element

Whenever a player casts an artifact, instant, or sorcery spell, you create a Mutagen token. (It's an artifact with "{1}, {T}, Sacrifice this token: Put a +1/+1 counter on target creature. Activate only as a sorcery.")

Harnfel, Horn of Bounty

Discard a card: Exile the top two cards of your library. You may play those cards this turn.

Birgi, God of Storytelling

Whenever you cast a spell, add {R}. Until end of turn, you don't lose this mana as steps and phases end.
Creatures you control can boast twice during each of your turns rather than once.

Birgi, God of Storytelling // Harnfel, Horn of Bounty

The Great Work

(As this Saga enters and after your draw step, add a lore counter.)
I — This Saga deals 3 damage to target opponent and each creature they control.
II — Create three Treasure tokens.
III — Until end of turn, you may cast instant and sorcery spells from any graveyard. If a spell cast this way would be put into a graveyard, exile it instead. Exile this Saga, then return it to the battlefield (front face up).

Urabrask

First strike
Whenever you cast an instant or sorcery spell, Urabrask deals 1 damage to target opponent. Add {R}.
{R}: Exile Urabrask, then return it to the battlefield transformed under its owner's control. Activate only as a sorcery and only if you've cast three or more instant and/or sorcery spells this turn.

Urabrask // The Great Work

Runaway Steam-Kin

Whenever you cast a red spell, if this creature has fewer than three +1/+1 counters on it, put a +1/+1 counter on this creature.
Remove three +1/+1 counters from this creature: Add {R}{R}{R}.

Clifftop Retreat

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

Glacial Fortress

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

Imperial Recruiter

When this creature enters, search your library for a creature card with power 2 or less, reveal it, put it into your hand, then shuffle.

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.")

Reverberate

Copy target instant or sorcery spell. You may choose new targets for the copy.

Island

Flooded Strand

{T}, Pay 1 life, Sacrifice this land: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Adarkar Wastes

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

Shivan Reef

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

Arcane Signet

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

Elemental Eruption

Create a 4/4 red Dragon Elemental creature token with flying and prowess.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Dual Strike

When you next cast an instant or sorcery spell with mana value 4 or less this turn, copy that spell. You may choose new targets for the copy.
Foretell {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.)

Sol Ring

Plains

Sacred Foundry

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

Sea of Clouds

This land enters tapped unless you have two or more opponents.
{T}: Add {W} or {U}.

Recruiter of the Guard

When this creature enters, you may search your library for a creature card with toughness 2 or less, reveal it, put it into your hand, then shuffle.

Arid Mesa

{T}, Pay 1 life, Sacrifice this land: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.

Burning Sun's Fury

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Up to two target creatures each get +2/+0 and gain haste until end of turn.

Turbulent Springs

({T}: Add {U} or {R}.)
This land enters tapped unless your opponents control eight or more lands.

Repeated Reverberation

When you next cast an instant spell, cast a sorcery spell, or activate a loyalty ability this turn, copy that spell or ability twice. You may choose new targets for the copies.

Goblin Wizardry

Create two 1/1 red Goblin Wizard creature tokens with prowess. (Whenever you cast a noncreature spell, they get +1/+1 until end of turn.)

Increasing Vengeance

Copy target instant or sorcery spell you control. If this spell was cast from a graveyard, copy that spell twice instead. You may choose new targets for the copies.
Flashback {3}{R}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Cloud, Midgar Mercenary

When Cloud enters, search your library for an Equipment card, reveal it, put it into your hand, then shuffle.
As long as Cloud is equipped, if a triggered ability of Cloud or an Equipment attached to it triggers, that ability triggers an additional time.

Scalding Tarn

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

Kozilek, Butcher of Truth

When you cast this spell, draw four cards.
Annihilator 4 (Whenever this creature attacks, defending player sacrifices four permanents of their choice.)
When Kozilek is put into a graveyard from anywhere, its owner shuffles their graveyard into their library.

Prismari Command

Choose two —
• Prismari Command deals 2 damage to any target.
• Target player draws two cards, then discards two cards.
• Target player creates a Treasure token.
• Destroy target artifact.

Bludgeon Brawl

Each noncreature, non-Equipment artifact is an Equipment with equip {X} and "Equipped creature gets +X/+0," where X is that artifact's mana value.

Exotic Orchard

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

Puresteel Paladin

Whenever an Equipment you control enters, you may draw a card.
Metalcraft — Equipment you control have equip {0} as long as you control three or more artifacts.

Krile Baldesion

Lifelink
Trace Aether — Whenever you cast a noncreature spell, you may return target creature card with mana value equal to that spell's mana value from your graveyard to your hand. Do this only once each turn.

Sunforger

Equipped creature gets +4/+0.
{R}{W}, Unattach this Equipment: Search your library for a red or white instant card with mana value 4 or less and cast that card without paying its mana cost. Then shuffle.
Equip {3}

Painter's Servant

As this creature 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.

Tataru Taru

When Tataru Taru enters, you draw a card and target opponent may draw a card.
Scions' Secretary — Whenever an opponent draws a card, if it isn't that player's turn, create a tapped Treasure token. This ability triggers only once each turn.

Training Center

This land enters tapped unless you have two or more opponents.
{T}: Add {U} or {R}.

Battlefield Forge

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

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.")

Hallowed Fountain

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

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.

Spectator Seating

This land enters tapped unless you have two or more opponents.
{T}: Add {R} or {W}.

Otterball Antics

Create a 1/1 blue and red Otter creature token with prowess. If this spell was cast from anywhere other than your hand, put a +1/+1 counter on that creature. (Whenever you cast a noncreature spell, a creature with prowess gets +1/+1 until end of turn.)
Flashback {3}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Sokka and Suki

Whenever Sokka and Suki or another Ally you control enters, attach up to one target Equipment you control to that creature.
Whenever an Equipment you control enters, create a 1/1 white Ally creature token.

Reliquary Tower

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

Command Tower

Crime Novelist

Whenever you sacrifice an artifact, put a +1/+1 counter on this creature and add {R}.

Dwarven Recruiter

When this creature enters, search your library for any number of Dwarf cards, reveal them, then shuffle and put those cards on top in any order.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Steam Vents

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

Unexpected Windfall

The Seriema

When The Seriema enters, search your library for a legendary creature card, reveal it, put it into your hand, then shuffle.
Station (Tap another creature you control: Put charge counters equal to its power on this Spacecraft. Station only as a sorcery. It's an artifact creature at 7+.)
7+ | Flying
Other tapped legendary creatures you control have indestructible.

Fury Storm

When you cast this spell, copy it for each time you've cast your commander from the command zone this game. You may choose new targets for the copies.
Copy target instant or sorcery spell. You may choose new targets for the copy.

Sulfur Falls

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

Mountain

Flick a Coin

Flick a Coin deals 1 damage to any target. You create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
Draw a card.

Rally the Monastery

This spell costs {2} less to cast if you've cast another spell this turn.
Choose one —
• Create two 1/1 white Monk creature tokens with prowess.
• Up to two target creatures you control each get +2/+2 until end of turn.
• Destroy target creature with power 4 or greater.

Tempt with Mayhem

Tempting offer — Choose target instant or sorcery spell. Each opponent may copy that spell and may choose new targets for the copy they control. You copy that spell once plus an additional time for each opponent who copied the spell this way. You may choose new targets for the copies you control.

Geistblast

Geistblast deals 2 damage to any target.
{2}{U}, Exile this card from your graveyard: Copy target instant or sorcery spell you control. You may choose new targets for the copy.

Dan Lewis

Noncreature, non-Equipment artifacts you control are Equipment in addition to their other types and have "Equipped creature gets +1/+0" and equip {1}.
Doctor's companion (You can have two commanders if the other is the Doctor.)

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.

Turbulent Steppe

({T}: Add {R} or {W}.)
This land enters tapped unless your opponents control eight or more lands.

Reiterate

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)
Copy target instant or sorcery spell. You may choose new targets for the copy.