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.

Fiery Inscription

When Fiery Inscription enters, the Ring tempts you.
Whenever you cast an instant or sorcery spell, Fiery Inscription deals 2 damage to each opponent.

Firemind's Research

Whenever you cast an instant or sorcery spell, put a charge counter on Firemind's Research.
{1}{U}, Remove two charge counters from Firemind's Research: Draw a card.
{1}{R}, Remove five charge counters from Firemind's Research: It deals 5 damage to any target.

Tectonic Hazard

Tectonic Hazard deals 1 damage to each opponent and each creature they control.

Didn't Say Please

Counter target spell. Its controller mills three cards.

Kessig Flamebreather

Whenever you cast a noncreature spell, Kessig Flamebreather deals 1 damage to each opponent.

Sweltering Suns

Sweltering Suns deals 3 damage to each creature.
Cycling {3} ({3}, Discard this card: Draw a card.)

Gandalf, Friend of the Shire

Flash
You may cast sorcery spells as though they had flash.
Whenever the Ring tempts you, if you chose a creature other than Gandalf, Friend of the Shire as your Ring-bearer, draw a card.

Aether Gale

Return six target nonland permanents to their owners' hands.

Winterflame

Choose one or both —
• Tap target creature.
• Winterflame deals 2 damage to target creature.

Mizzix's Mastery

Exile target card that's an instant or sorcery from your graveyard. For each card exiled this way, copy it, and you may cast the copy without paying its mana cost. Exile Mizzix's Mastery.
Overload {5}{R}{R}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Repercussion

Whenever a creature is dealt damage, Repercussion deals that much damage to that creature's controller.

Beacon Bolt

Beacon Bolt deals damage to target creature equal to the total number of instant and sorcery cards you own in exile and in your graveyard.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)

Guttersnipe

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

Chimil, the Inner Sun

Spells you control can't be countered.
At the beginning of your end step, discover 5. (Exile cards from the top of your library until you exile a nonland card with mana value 5 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Mind Spring

Cyclone Summoner

When Cyclone Summoner enters, if you cast it from your hand, return all permanents to their owners' hands except for Giants, Wizards, and lands.

Thought Vessel

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

Pull from Tomorrow

Display of Power

This spell can't be copied.
Copy any number of target instant and/or sorcery spells. You may choose new targets for the copies.

Cast into the Fire

Choose one —
• Cast into the Fire deals 1 damage to each of up to two target creatures.
• Exile target artifact.

Cancel

Izzet Guildmage

({U/R} can be paid with either {U} or {R}.)
{2}{U}: Copy target instant spell you control with mana value 2 or less. You may choose new targets for the copy.
{2}{R}: Copy target sorcery spell you control with mana value 2 or less. You may choose new targets for the copy.

Prophetic Bolt

Prophetic Bolt deals 4 damage to any target. Look at the top four cards of your library. Put one of those cards into your hand and the rest on the bottom of your library in any order.

Goblin Electromancer

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

Izzet Chronarch

When Izzet Chronarch enters, return target instant or sorcery card from your graveyard to your hand.

Invent

Search your library for an instant card and/or a sorcery card, reveal them, put them into your hand, then shuffle.

Invert

Switch the power and toughness of each of up to two target creatures until end of turn.

Invert // Invent

Ophidian Eye

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Breath Weapon

Breath Weapon deals 2 damage to each non-Dragon creature.

Dissipate

Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Abrade

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

Electrify

Electrify deals 4 damage to target creature.

Baral, Chief of Compliance

Instant and sorcery spells you cast cost {1} less to cast.
Whenever a spell or ability you control counters a spell, you may draw a card. If you do, discard a card.

Vandalblast

Destroy target artifact you don't control.
Overload {4}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Case of the Ransacked Lab

Instant and sorcery spells you cast cost {1} less to cast.
To solve — You've cast four or more instant and sorcery spells this turn. (If unsolved, solve at the beginning of your end step.)
Solved — Whenever you cast an instant or sorcery spell, draw a card.

Master the Way

Draw a card. Master the Way deals damage to any target equal to the number of cards in your hand.

Highland Lake

Highland Lake enters tapped.
{T}: Add {U} or {R}.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

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.

Neutralizing Blast

Star of Extinction

Destroy target land. Star of Extinction deals 20 damage to each creature and each planeswalker.

Gale, Waterdeep Prodigy

Whenever you cast an instant or sorcery spell from your hand, you may cast up to one target card of the other type from your graveyard. If a spell cast from your graveyard this way would be put into your graveyard, exile it instead.
Choose a Background (You can have a Background as a second commander.)

Curiosity

Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Ral, Crackling Wit

Whenever you cast a noncreature spell, put a loyalty counter on Ral, Crackling Wit.
+1: Create a 1/1 blue and red Otter creature token with prowess.
−3: Draw three cards, then discard two cards.
−10: Draw three cards. You get an emblem with "Instant and sorcery spells you cast have storm." (Whenever you cast an instant or sorcery spell, copy it for each spell cast before it this turn.)

Magmaquake

Magmaquake deals X damage to each creature without flying and each planeswalker.

Galvanic Iteration

When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.
Flashback {1}{U}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Gandalf the Grey

Whenever you cast an instant or sorcery spell, choose one that hasn't been chosen —
• You may tap or untap target permanent.
• Gandalf the Grey deals 3 damage to each opponent.
• Copy target instant or sorcery spell you control. You may choose new targets for the copy.
• Put Gandalf on top of its owner's library.

Reliquary Tower

Blazing Volley

Blazing Volley deals 1 damage to each creature your opponents control.

Anticognition

Counter target creature or planeswalker spell unless its controller pays {2}. If an opponent has eight or more cards in their graveyard, instead counter that spell, then scry 2.

Fire Servant

If a red instant or sorcery spell you control would deal damage, it deals double that damage instead.

Tempest Angler

Whenever you cast a noncreature spell, put a +1/+1 counter on Tempest Angler.

Arrester's Admonition

Return target creature to its owner's hand.
Addendum — If you cast this spell during your main phase, draw a card.

Hour of Devastation

All creatures lose indestructible until end of turn. Hour of Devastation deals 5 damage to each creature and each non-Bolas planeswalker.

Blasphemous Act

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

Pearl of Wisdom

This spell costs {1} less to cast if you control an Otter.
Draw two cards.

Sonic Assault

Tap target creature. Sonic Assault deals 2 damage to that creature's controller.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)

Baral and Kari Zev

First strike, menace
Whenever you cast your first instant or sorcery spell each turn, you may cast a spell with lesser mana value that shares a card type with it from your hand without paying its mana cost. If you don't, create First Mate Ragavan, a legendary 2/1 red Monkey Pirate creature token. It gains haste until end of turn.

Island

Hurkyl's Final Meditation

During turns other than yours, this spell costs {3} more to cast.
Return all nonland permanents to their owners' hands. End the turn. (Exile all spells and abilities from the stack, including this card. The player whose turn it is discards down to their maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)

Mountain

Fiery Emancipation

If a source you control would deal damage to a permanent or player, it deals triple that damage to that permanent or player instead.

Spellbook

Cunning Strike

Cunning Strike deals 2 damage to target creature and 2 damage to target player or planeswalker.
Draw a card.

Essence Backlash

Counter target creature spell. Essence Backlash deals damage equal to that spell's power to its controller.

Essence Scatter

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Quench

Counter target spell unless its controller pays {2}.

Izzet Charm

Choose one —
• Counter target noncreature spell unless its controller pays {2}.
• Izzet Charm deals 2 damage to target creature.
• Draw two cards, then discard two cards.

Chain Reaction

Chain Reaction deals X damage to each creature, where X is the number of creatures on the battlefield.

Izzet Guildgate

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

Unexplained Vision

Draw three cards.
Adamant — If at least three blue mana was spent to cast this spell, scry 3.

Galvanoth

At the beginning of your upkeep, you may look at the top card of your library. You may cast it without paying its mana cost if it's an instant or sorcery spell.

Alania, Divergent Storm

Whenever you cast a spell, if it's the first instant spell, the first sorcery spell, or the first Otter spell other than Alania you've cast this turn, you may have target opponent draw a card. If you do, copy that spell. You may choose new targets for the copy.

Najal, the Storm Runner

You may cast sorcery spells as though they had flash.
Whenever Najal, the Storm Runner attacks, you may pay {2}. If you do, when you next cast an instant or sorcery spell this turn, copy it. You may choose new targets for the copy.

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.

Starstorm

Starstorm deals X damage to each creature.
Cycling {3} ({3}, Discard this card: Draw a card.)

Niv-Mizzet, the Firemind

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

Swiftwater Cliffs

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {U} or {R}.

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.

Mizzium Mortars

Mizzium Mortars deals 4 damage to target creature you don't control.
Overload {3}{R}{R}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Mob Rule

Choose one —
• Gain control of all creatures with power 4 or greater until end of turn. Untap those creatures. They gain haste until end of turn.
• Gain control of all creatures with power 3 or less until end of turn. Untap those creatures. They gain haste until end of turn.