msem-instigator

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.

Counter target spell.

Flash
Whenever Mischievous Capuchin or another Monk you control enters, tap target creature you don't control. If it was already tapped, it doesn't untap during its controller's next untap step.

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

Create a 1/1 blue Illusion creature token with “This gets +1/+1 for each other Illusion you control.”
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)

[+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.”

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

You may play an additional land on each of your turns.
{4}{U}{U}: Transform Misthollow Rites. Activate only as a sorcery.

Mistwake Hydra enters with X +1/+1 counters on it.
Creatures with power less than Mistwake Hydra's power can't block it.

Flying, haste
Miyoga Firebird attacks each combat if able.
Whenever you cast your third instant or sorcery spell this turn, you may return Miyoga Firebird from your graveyard to the battlefield.

Flying, haste
Miyoga Flameweaver can't block.
Whenever Miyoga Flameweaver attacks, exile the top card of your library. You may play that card until end of turn.

Creatures you control with flying get +1/+1.
Whenever a creature you control with flying deals combat damage to a player, you may pay {U}. If you do, draw a card.

Create a token that's a copy of target creature you control.
Fabled {5}{U}{U} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

Modular Mercenary gets +1/+0 and has first strike as long as you control a creature with a +1/+1 counter on it.

First strike, haste
When Moeru Thunderers enters, if it's not a token, create a token that's a copy of it, except it has no mana cost.

Flash
When Mokuteki Ambusher enters, until end of turn, other creatures you control gain “{T}: This creature deals 1 damage to any target.”

Gestalt (When this or another creature enters under your control, you may merge it with the one in play, keeping counters and attachments. They become the permanent on top plus all abilities from under it.)
Double strike
If this creature would deal noncombat damage, it deals double that damage instead.

When Monk of Mid-Autumn enters, choose one —
• Put a double strike counter on Monk of Mid-Autumn.
• Destroy target artifact or enchantment.
• Monk of Mid-Autumn deals 2 damage to target tapped creature and you gain 2 life.

{T}: Add {G} or {U}.
{G}{U}, {T}: Return target creature you control to its owner's hand.

Vanguard — Whenever a creature you control attacks alone, that creature gets +3/+0 until end of turn.

Lifelink
At the beginning of your end step, you gain 1 life if you gained life this turn, and each opponent that lost life this turn loses 1 life.

Whenever you gain life, you may put target creature or planeswalker card from your graveyard on top of your library.

As Moonlight Sanctum enters, choose Waxing or Waning.
• Waxing — At the beginning of your upkeep, you gain 1 life for each enchantment you control.
• Waning — Nonenchantment spells cost {1} more to cast.

Flying
When Moonlit Charmer enters, tap target artifact or creature. It doesn't untap during its controller's next untap step.

Whenever Moonlit Lurker blocks, put a +1/+1 counter on it.