Doublecast

When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.

Twinflame

Strive — This spell costs {2}{R} more to cast for each target beyond the first.
Choose any number of target creatures you control. For each of them, create a token that's a copy of that creature, except it has haste. Exile those tokens at the beginning of the next end step.

Double Negative

Rage Reflection

Creatures you control have double strike.

The Royal Scions

+1: Draw a card, then discard a card.
+1: Target creature gets +2/+0 and gains first strike and trample until end of turn.
−8: Draw four cards. When you do, The Royal Scions deals damage to any target equal to the number of cards in your hand.

Reflection of Kiki-Jiki

{1}, {T}: Create a token that's a copy of another target nonlegendary creature you control, except it has haste. Sacrifice it at the beginning of the next end step.

Fable of the Mirror-Breaker

(As this Saga enters and after your draw step, add a lore counter.)
I — Create a 2/2 red Goblin Shaman creature token with "Whenever this creature attacks, create a Treasure token."
II — You may discard up to two cards. If you do, draw that many cards.
III — Exile this Saga, then return it to the battlefield transformed under your control.

Fable of the Mirror-Breaker // Reflection of Kiki-Jiki

Double Major

Copy target creature spell you control, except it isn't legendary if the spell is legendary. (A copy of a creature spell becomes a token.)

Dawn's Reflection

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional two mana in any combination of colors.

Riku of Two Reflections

Whenever you cast an instant or sorcery spell, you may pay {U}{R}. If you do, copy that spell. You may choose new targets for the copy.
Whenever another nontoken creature you control enters, you may pay {G}{U}. If you do, create a token that's a copy of that creature.

Dragon-Style Twins

Double strike
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Will Kenrith

+2: Until your next turn, up to two target creatures each have base power and toughness 0/3 and lose all abilities.
−2: Target player draws two cards. Until your next turn, instant, sorcery, and planeswalker spells that player casts cost {2} less to cast.
−8: Target player gets an emblem with "Whenever you cast an instant or sorcery spell, copy it. You may choose new targets for the copy."
Partner with Rowan Kenrith
Will Kenrith can be your commander.

Twin Bolt

Twin Bolt deals 2 damage divided as you choose among one or two targets.

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.

Adrix and Nev, Twincasters

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
If one or more tokens would be created under your control, twice that many of those tokens are created instead.

Twin-Silk Spider

Reach
When Twin-Silk Spider enters, create a 1/2 green Spider creature token with reach.

Desolation Twin

When you cast this spell, create a 10/10 colorless Eldrazi creature token.

Splinter Twin

Enchant creature
Enchanted creature has "{T}: Create a token that's a copy of this creature, except it has haste. Exile that token at the beginning of the next end step."

Stunt Double

Flash
You may have Stunt Double enter as a copy of any creature on the battlefield.

Ghastbark Twins

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Ghastbark Twins can block an additional creature each combat.

Body Double

You may have Body Double enter as a copy of any creature card in a graveyard.

Trueheart Twins

You may exert Trueheart Twins as it attacks. (It won't untap during your next untap step.)
Whenever you exert a creature, creatures you control get +1/+0 until end of turn.

Dreadhorde Twins

When Dreadhorde Twins enters, amass Zombies 2. (Put two +1/+1 counters on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)
Zombie tokens you control have trample.

Double Vision

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

Rowan Kenrith

+2: During target player's next turn, each creature that player controls attacks if able.
−2: Rowan Kenrith deals 3 damage to each tapped creature target player controls.
−8: Target player gets an emblem with "Whenever you activate an ability that isn't a mana ability, copy it. You may choose new targets for the copy."
Partner with Will Kenrith
Rowan Kenrith can be your commander.

Spark Double

You may have Spark Double enter as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Tempt with Reflections

Tempting offer — Choose target creature you control. Create a token that's a copy of that creature. Each opponent may create a token that's a copy of that creature. For each opponent who does, create a token that's a copy of that creature.

Twincast

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

Twinscroll Shaman

Stangg

When Stangg enters, create Stangg Twin, a legendary 3/4 red and green Human Warrior creature token. Exile that token when Stangg leaves the battlefield. Sacrifice Stangg when that token leaves the battlefield.