Dual Casting

Enchant creature
Enchanted creature has "{R}, {T}: Copy target instant or sorcery spell you control. You may choose new targets for the copy."

Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

Double Vision

Whenever you cast your first instant or sorcery spell each turn, copy that spell. You may choose new targets for the copy.

Firebrand Archer

Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent.

Renegade Tactics

Target creature can't block this turn.
Draw a card.

Decree of Pain

Destroy all creatures. They can't be regenerated. Draw a card for each creature destroyed this way.
Cycling {3}{B}{B} ({3}{B}{B}, Discard this card: Draw a card.)
When you cycle Decree of Pain, all creatures get -2/-2 until end of turn.

Demonic Tutor

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

Jet Medallion

Black spells you cast cost {1} less to cast.

Gamble

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

Aria of Flame

When Aria of Flame enters, each opponent gains 10 life.
Whenever you cast an instant or sorcery spell, put a verse counter on Aria of Flame, then it deals damage equal to the number of verse counters on it to target player or planeswalker.

Helm of the Host

At the beginning of combat on your turn, create a token that's a copy of equipped creature, except the token isn't legendary. That token gains haste.
Equip {5}

Necropotence

Skip your draw step.
Whenever you discard a card, exile that card from your graveyard.
Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.

Primal Wellspring

(Transforms from Primal Amulet.)
{T}: Add one mana of any color. When that mana is spent to cast an instant or sorcery spell, copy that spell and you may choose new targets for the copy.

Primal Amulet

Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell, put a charge counter on Primal Amulet. Then if there are four or more charge counters on it, you may remove those counters and transform it.

Primal Amulet // Primal Wellspring

Bösium Strip

{3}, {T}: Until end of turn, you may cast instant and sorcery spells from the top of your graveyard. If a spell cast this way would be put into a graveyard, exile it instead.

Sentinel Tower

Whenever an instant or sorcery spell is cast during your turn, Sentinel Tower deals damage to any target equal to 1 plus the number of instant and sorcery spells cast before that spell this turn.

Sol Ring

Swamp

Dark Dabbling

Regenerate target creature. Draw a card. (The next time the creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, also regenerate each other creature you control.

Shadow Rift

Target creature gains shadow until end of turn. (It can block or be blocked by only creatures with shadow.)
Draw a card.

Spark of Creativity

Choose target creature. Exile the top card of your library. You may have Spark of Creativity deal damage to that creature equal to the exiled card's mana value. If you don't, you may play that card until end of turn.

Mystic Retrieval

Return target instant or sorcery card from your graveyard to your hand.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

The Mirari Conjecture

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Return target instant card from your graveyard to your hand.
II — Return target sorcery card from your graveyard to your hand.
III — Until end of turn, whenever you cast an instant or sorcery spell, copy it. You may choose new targets for the copy.

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.

Twinning Staff

If you would copy a spell one or more times, instead copy it that many times plus an additional time. You may choose new targets for the additional copy.
{7}, {T}: Copy target instant or sorcery spell you control. You may choose new targets for the copy.

Thermo-Alchemist

Defender
{T}: Thermo-Alchemist deals 1 damage to each opponent.
Whenever you cast an instant or sorcery spell, untap Thermo-Alchemist.

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.

Overwhelming Forces

Destroy all creatures target opponent controls. Draw a card for each creature destroyed this way.

Mindclaw Shaman

When Mindclaw Shaman enters, target opponent reveals their hand. You may cast an instant or sorcery spell from among those cards without paying its mana cost.

Gitaxian Probe

({U/P} can be paid with either {U} or 2 life.)
Look at target player's hand.
Draw a card.

Island

Wildfire Devils

When Wildfire Devils enters and at the beginning of your upkeep, choose a player at random. That player exiles an instant or sorcery card from their graveyard. Copy that card. You may cast the copy without paying its mana cost.

Fire Diamond

Fire Diamond enters tapped.
{T}: Add {R}.

Arclight Phoenix

Flying, haste
At the beginning of combat on your turn, if you've cast three or more instant and sorcery spells this turn, return Arclight Phoenix from your graveyard to the battlefield.

Nighthaze

Target creature gains swampwalk until end of turn. (It can't be blocked as long as defending player controls a Swamp.)
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.)

Swarm Intelligence

Whenever you cast an instant or sorcery spell, you may copy that spell. You may choose new targets for the copy.

Silas Renn, Seeker Adept

Deathtouch
Whenever Silas Renn, Seeker Adept deals combat damage to a player, choose target artifact card in your graveyard. You may cast that card this turn.
Partner (You can have two commanders if both have partner.)

Crash Through

Creatures you control gain trample until end of turn. (Each of those creature can deal excess combat damage to the player or planeswalker it's attacking.)
Draw a card.

Cling to Dust

Exile target card from a graveyard. If it was a creature card, you gain 3 life. Otherwise, you draw a card.
Escape—{3}{B}, Exile five other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent of their choice or discards a card.

Crimson Wisps

Target creature becomes red and gains haste until end of turn. (It can attack and {T} this turn.)
Draw a card.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Aphotic Wisps

Target creature becomes black and gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)
Draw a card.

Backdraft Hellkite

Flying
Whenever Backdraft Hellkite attacks, each instant and sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost.

Guttersnipe

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

Arcane Signet

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

Insurrection

Untap all creatures and gain control of them until end of turn. They gain haste until end of turn.

Talent of the Telepath

Target opponent reveals the top seven cards of their library. You may cast an instant or sorcery spell from among them without paying its mana cost. Then that player puts the rest into their graveyard.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, you may cast up to two instant and/or sorcery spells from among the revealed cards instead of one.

Quicken

The next sorcery spell you cast this turn can be cast as though it had flash. (It can be cast any time you could cast an instant.)
Draw a card.

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.

Krark, the Thumbless

Whenever you cast an instant or sorcery spell, flip a coin. If you lose the flip, return that spell to its owner's hand. If you win the flip, copy that spell, and you may choose new targets for the copy.
Partner (You can have two commanders if both have partner.)

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

Overmaster

The next instant or sorcery spell you cast this turn can't be countered.
Draw a card.

Charmbreaker Devils

At the beginning of your upkeep, return an instant or sorcery card at random from your graveyard to your hand.
Whenever you cast an instant or sorcery spell, Charmbreaker Devils gets +4/+0 until end of turn.

Past in Flames

Each instant and sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost.
Flashback {4}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Krark's Thumb

If you would flip a coin, instead flip two coins and ignore one.

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Aetherflux Reservoir

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.
Pay 50 life: Aetherflux Reservoir deals 50 damage to any target.

Mystical Tutor

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

Pyromancer's Goggles

{T}: Add {R}. When that mana is spent to cast a red instant or sorcery spell, copy that spell and you may choose new targets for the copy.

Ruby Medallion

Red spells you cast cost {1} less to cast.

Preordain

Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Electrostatic Field

Defender
Whenever you cast an instant or sorcery spell, Electrostatic Field deals 1 damage to each opponent.

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.)

Wavebreak Hippocamp

Whenever you cast your first spell during each opponent's turn, draw a card.

Dockside Extortionist

When Dockside Extortionist enters, create X Treasure tokens, where X is the number of artifacts and enchantments your opponents control. (Treasure tokens are artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Bribery

Search target opponent's library for a creature card and put that card onto the battlefield under your control. Then that player shuffles.

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.