msem-instigator

Flying
When Mirin, Held by the Heavens dies, if your life total is less than 10, it becomes 10.

Whenever you cast a green or blue spell, create a 1/1 green and blue Elemental creature token.
Each Elemental you control enters with an additional +1/+1 counter on it.

Puzzlebox (Begin the game with this and another card you own from outside the game in the command zone, locked. That card is face down until you unlock this.)
When the fourth spell of a turn is cast, you may unlock Mirror Cipher. If the revealed card is an instant or sorcery card, cast it without paying its mana cost and copy it. You may choose new targets for the copy.

Reverberate {3}{U} (When you cast this spell, copy it if you paid its reverberate cost. You may choose new targets for the copy.)
Create a token that's a copy of target creature you control.

Sabotage — Whenever an opponent or permanent an opponent controls becomes the target of a spell you control, put a +1/+1 counter on Mirrorcast Battlemage.
Remove three +1/+1 counters from Mirrorcast Battlemage: Copy target instant or sorcery spell you control. You may choose new targets for the copy. Activate only once each turn.

Siphon (Each -1/-1 counter you put on your creatures up to their remaining toughness while casting this pays for {1}.)
Create a token that's a copy of target creature you control, except it enters with an additional -1/-1 counter on it.

Flying
Whenever you cast an instant or sorcery spell, put a +1/+1 counter on Mirrorfuse Angel, then copy that spell for each +1/+1 counter on Mirrorfuse Angel. You may choose new targets for the copies.

Mirrorgate enters tapped.
When Mirrorgate enters, you choose a nonbasic land card name other than Mirrorgate, then each player chooses a color.
Lands with the chosen name are lands with “{T}: Add one mana of any of the chosen colors,” and lose all other abilities, card types, and land types.
{T}: Add one mana of any of the chosen colors.

Whenever a player casts an instant or sorcery spell that targets only one target or activates an ability that targets only one target, copy that spell or ability for each other target it could target. Each copy targets a different one of those targets. (A spell or ability can't target itself.)

Prowess
Whenever you cast your first noncreature spell during each of your turns, create a 1/1 blue Reflection Wizard creature token with prowess.

When you cast this spell, copy it for each Reflection creature you control. You may choose new targets for the copies.
Mirrorstorm deals 1 damage to any target and you gain 1 life.

Flying, ward {2}
At the beginning of your upkeep, if Mirrorwing Commander is embattled, create a token that's a copy of it. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

[+1]: Scry 3.
[–2]: Choose a card name, then mill a card. If that card has the chosen name, you draw three cards. Otherwise, you draw a card.
[–6]: You get an emblem with “Play with the top card of your library revealed” and “You may play the top card of your library.”

Flash
Flying
When Mischievous Sprite enters,you may tap or untap target permanent.

When Miserable Portent enters, create a 1/1 black Harpy creature token with flying.
{3}{B}, Sacrifice Miserable Portent: You draw two cards and you lose 2 life.

Players play with the top card of their libraries revealed.
[+2]: Target player mills a card. Draw a card.
[+1]: Create a 1/1 blue Illusion creature token with “This gets +1/+1 for each other Illusion you control.”
[–4]: Return target creature card from a graveyard to the battlefield under your control. It's an Illusion in addition to its other types.

Put target creature into its owner's library third from the top.

Cast this spell only during the declare blockers step.
After this step there's an additional declare attackers step followed by an additional declare blockers step. (A creature can't attack or block again if it's already attacking or blocking.)
Draw a card.

Menace
At the beginning of your upkeep, if an opponent has more cards in hand than you, you draw a card and you lose 1 life.

[+2]: Target player exiles a card from their hand at random. Until the end of that player's next turn, they may play that card.
[0]: Gain control of target creature or planeswalker until end of turn. Tap it.
[–9]: Take an extra turn after this one. During that turn, you control all opponents.

[+2]: Create a Vial token. (It's an artifact with “1, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
[–3]: Sacrifice another nonland permanent. If you do, destroy target nonland permanent.
[–9]: You get an emblem with “At the beginning of your end step, create Fallen One, a legendary 6/6 black Faerie Angel Avatar creature token with flying.”

Noncreature spells your opponents cast cost {1} more to cast.
Unveil {2}{W}{U} ({2}{W}{U}: Transform this. Unveil only as a sorcery.)

Other creatures you control get +2/+0 and have menace.
Whenever another creature you control dies, if it wasn't sacrificed, sacrifice a creature.

Vigilance
Ignore all effects that would prevent Mistbreaker from attacking or blocking. (If an effect says it “can't” attack or block, it still can. This ability doesn't let it attack or block if it's tapped or attack if it has summoning sickness.)

You may play an additional land on each of your turns.
Landfall — Whenever a land you control enters, draw a card.