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.

Inspiring Refrain

Draw two cards. Exile Inspiring Refrain with three time counters on it.
Suspend 3—{2}{U} (Rather than cast this card from your hand, you may pay {2}{U} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Blue Sun's Twilight

Gain control of target creature with mana value X or less. If X is 5 or more, create a token that's a copy of that creature.

Epic Experiment

Exile the top X cards of your library. You may cast instant and sorcery spells with mana value X or less from among them without paying their mana costs. Then put all cards exiled this way that weren't cast into your graveyard.

Alchemist's Gambit

Cleave {4}{U}{U}{R} (You may cast this spell for its cleave cost. If you do, remove the words in square brackets.)
Take an extra turn after this one. During that turn, damage can't be prevented. [At the beginning of that turn's end step, you lose the game.]
Exile Alchemist's Gambit.

Chain Reaction

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

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.

Drawn from Dreams

Look at the top seven cards of your library. Put two of them into your hand and the rest on the bottom of your library in a random order.

Melek, Izzet Paragon

Play with the top card of your library revealed.
You may cast instant and sorcery spells from the top of your library.
Whenever you cast an instant or sorcery spell from your library, copy it. You may choose new targets for the copy.

Explosion

Explosion deals X damage to any target. Target player draws X cards.

Expansion

Copy target instant or sorcery spell with mana value 4 or less. You may choose new targets for the copy.

Expansion // Explosion

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.

Dualcaster Mage

Flash
When Dualcaster Mage enters, copy target instant or sorcery spell. You may choose new targets for the copy.

Jaya, Fiery Negotiator

+1: Create a 1/1 red Monk creature token with prowess.
−1: Exile the top two cards of your library. Choose one of them. You may play that card this turn.
−2: Choose target creature an opponent controls. Whenever you attack this turn, Jaya, Fiery Negotiator deals damage equal to the number of attacking creatures to that creature.
−8: You get an emblem with "Whenever you cast a red instant or sorcery spell, copy it twice. You may choose new targets for the copies."

Blasphemous Act

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

Swarm Intelligence

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

Teferi's Talent

Enchant planeswalker
Enchanted planeswalker has "[−12]: You get an emblem with 'You may activate loyalty abilities of planeswalkers you control on any player's turn any time you could cast an instant.'"
Whenever you draw a card, put a loyalty counter on enchanted planeswalker.

Invoke the Winds

Gain control of target artifact or creature. Untap it.

Rowan's Talent

Enchant planeswalker
Enchanted planeswalker has "[+1]: Up to one target creature gets +2/+0 and gains first strike and trample until end of turn."
Whenever you activate a loyalty ability of enchanted planeswalker, copy that ability. You may choose new targets for the copy.

Grapeshot

Grapeshot deals 1 damage to any target.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Clone Legion

For each creature target player controls, create a token that's a copy of that creature.

Wild Ricochet

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

River's Rebuke

Return all nonland permanents target player controls to their owner's hand.

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.

Silver Scrutiny

You may cast Silver Scrutiny as though it had flash if X is 3 or less.
Draw X cards.

Creative Technique

Demonstrate (When you cast this spell, you may copy it. If you do, choose an opponent to also copy it.)
Shuffle your library, then reveal cards from the top of it until you reveal a nonland card. Exile that card and put the rest on the bottom of your library in a random order. You may cast the exiled card without paying its mana cost.