msem-instigator

When Mental Supremacist enters, choose target creature you don't control. That creature has base power and toughness 1/1 and loses all abilities for as long as you control Mental Supremacist.

Other Elementals you control get +2/+2.
Whenever one or more Elementals you control attack, tap up to one target creature you don't control.

Whenever another creature with power 4 or greater you control enters, you may draw a card.

{T}: Add {C}.
Satrapies you control enter untapped.

Flying, vigilance
Prevent all damage Merciful Yuroda would deal to creatures.

Infiltrate (Whenever one or more attacking creatures you control aren't blocked, this creature gets +1/+1 until end of turn.)
Whenever Merciless Exiled deals combat damage to a player, scry 2.

Whenever one or more creatures deal combat damage to you, exile one of those creatures.
You may cast cards exiled with Merciless Mirror and may spend mana as though it were mana of any color to cast those spells.

Whenever Merciless Shieldbreaker enters or attacks, target opponent puts three rust counters on a permanent they control with no rust counters on it. That permanent gains “At the beginning of your upkeep, remove a rust counter from this permanent. Then if there are no rust counters on this permanent, sacrifice it and it deals 4 damage to you.”

{2}{G/U}{G/U}, {T}: Untap each non-Lizard permanent you control.

This spell can't be countered.
Whenever Meren, Bane of the Cairns attacks, exile target creature card from your graveyard. You may cast that card for as long as it remains exiled by sacrificing a creature in addition to paying its other costs.

Choose two —
• Counter target spell unless its controller pays {6}.
• Target player draws two cards, then discards a card.
• Creatures target player doesn't control get -3/-0 until end of turn.
• Exile up to two target creatures, then return those cards to the battlefield under their owners' control.

Flying, haste
{X}{R}{R}, Exile an instant or sorcery card with mana value X from your graveyard: Return Merkurio's Familiar from your graveyard to the battlefield. It gets +X/+0 until end of turn.

Draw three cards.
Reprise {5}{U}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Whenever Merrow Legendmaker attacks, look at the top five cards of your library. You may reveal an Aura, Aurashaper, or Equipment card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Survivors you control get +3/+3.

Enchant creature
When Mesmerizing Shimmer enters, untap enchanted creature. It gains haste until end of turn.
You control enchanted creature.
Mirage {2}{U}{R} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Flying
When Messenger of the Heavens enters, surveil 1.
Whenever Messenger of the Heavens deals combat damage to a player, exile any number of target creatures in its pack, then return them to the battlefield under your control. (Two or more creatures you control with equal power are in a pack.)

Choose one —
• Meteor Fall deals 4 damage to each creature and each planeswalker.
• Meteor Fall deals 8 damage to target creature or planeswalker.

When Meteor Harbinger enters, choose one —
• Meteor Harbinger deals 2 damage to each creature.
• Each player sacrifices two lands.
• Meteor Harbinger deals 2 damage to each of two target players or planeswalkers.

Meteor Volley deals 3 damage to each creature.
Reprise {4}{R}{R} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Harness (You may tap a creature you control as you cast this spell. If you do, reduce this spell's mana cost by that creature's power.)
Exile the top three cards of your library. Cast a spell with mana value X or less from among them without paying its mana cost.

Mettalia is all colors.
Mettalia has protection from each color among cards she's salvaged in exile.
When Mettalia enters, for each color, you may salvage a nonlegendary card of that color. (Exile one from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)

Whenever a land you control enters, crystallize.
{10}: Shuffle any number of other permanents you control into their owner's library. Mill that many cards. Put all permanent cards milled this way onto the battlefield. Activate only during your turn and only once each turn.

Whenever you discard a card, choose up to one that hasn't been chosen this turn —
• Draw a card.
• Tap target creature. Put a stun counter on it.
• Create a 2/2 blue Jellyfish enchantment creature token with flying.

Flash
Wanderlust — When Microzoologist enters, search your library for a creature card with mana value 1. If you control four or more differently named lands, you may search for a creature card with mana value 3 or less instead. Reveal that card, put it into your hand, then shuffle.