msem-instigator

As Mind-Mute enters, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.
{5}: Return Mind-Mute to its owner's hand.

Lifelink
Mind-Pryer gets +1/+1 as long as an opponent has one or fewer cards in hand.
Whenever an opponent discards a card, Mind-Pryer cackles. (Put a menace counter on it. If it already has menace, it deals 1 damage to each opponent instead.)

When Mindbreak Artisan enters, you may search your library for an artifact card, reveal it, shuffle, then put that card on top.
Other artifacts you control have “You may choose not to untap this artifact during your untap step” and “{3}{U}{U}, {T}: Gain control of target creature for as long as you control this artifact and it remains tapped.”

Flying
If Mindbreaker Sphinx would deal combat damage to a player, you may prevent it. If you do, that player mills X cards, where X is Mindbreaker Sphinx's power. If two cards that share a card type were milled this way, put a +1/+1 counter on Mindbreaker Sphinx.

Counter target spell. Search its controller's library for a card with mana value X or less and cast it without paying its mana cost. Then that player shuffles.

Exile target spell. Then that card's owner may return it to their hand. If they do, draw a card.

Discard your hand, then draw three cards.
Mindstorm's Eye deals 3 damage to any target.

When Mindwave Rod enters, attach it to target creature you control.
Equipped creature gets +1/+1 and has “Whenever this creature deals combat damage to a player, draw a card.”
Equip {2}

When Minister of Madness enters, create a 0/1 blue Weird creature token with flying.
{2}{U}, Sacrifice a creature: Search your library for an instant or sorcery card with mana value equal to 1 plus the sacrificed creature's mana value, exile that card, then shuffle. Then you may cast that card without paying its mana cost. Activate only as a sorcery.

At the beginning of combat on your turn, create a 1/1 red Cleric creature token with haste.
At the beginning of your end step, sacrifice each Cleric token you control unless you've cast an instant or sorcery spell this turn.

Menace
When Minotaur Skullsmasher enters, choose a nonland card type. Then target opponent reveals their hand. You choose a card of the chosen type from it. That player discards that card.

Flying, deathtouch
Whenever an opponent loses life for the first time each turn, that player loses 1 life and you gain 1 life.

Whenever another nontoken creature you control dies, you may exile it. If you do, create a token that's a copy of it, except it has base power and toughness 1/1. If that creature had power 4 or greater, create two of those tokens instead.

Heroic — Whenever you cast a spell that targets Mira and Kalisti of Akros, copy that spell. You may choose new targets for the copy. (The copy isn't cast. A copy of an Aura spell becomes a token.)

Starting with you, each player may put a permanent card from their hand onto the battlefield. Then each player may choose a noncreature, nonland permanent. Destroy those permanents.

Shimmer (Whenever this creature attacks, create a tapped and attacking token that's a copy of it. Exile the token at the beginning of the end step.)
{2}{G}, {T}: Create a token that's a copy of target creature token.

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

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.

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.

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.