msem-instigator

Armed — Merciless Brute gets +2/+2 as long as it's equipped.

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.

Menace
Ferocious — Whenever Merciless Xun Huang attacks, if you control a creature with power 4 or greater, defending player sacrifices a permanent.

Whenever Merfolk Visionary or another Merfolk creature you control enters, scry 2. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

[+1]: Merkurio deals 2 damage to target player or planeswalker. That player or that planeswalker's controller may draw a card.
[–2]: The next instant or sorcery spell you cast this turn costs {U}{R} less to cast. This effect reduces only the amount of colored mana you pay.
[–7]: You get an emblem with “Each instant and sorcery card you own has reverberate {X}, where X is its mana value.” (When you cast a spell, copy it if you paid its reverberate cost. You may choose new targets for the copy.)

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.

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.)

Kicker {2} (You may pay an additional {2} as you cast this spell.)
Prowess
When Merkurio's Opus enters, if it was kicked, draw two cards, then discard two cards.

Counter target spell unless its controller pays {2} for each Wizard on the battlefield.

Return target nonland permanent to its owner's hand.
Reprise {2}{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.)

[+1]: The next instant or sorcery spell you cast this turn costs {1} less to cast.
[–4]: Until end of turn, whenever you cast an instant or sorcery spell, Merkurio deals 2 damage to any target.
[–8]: Exile the top seven cards of your library. You may cast any number of instant and sorcery cards from among them without paying their mana costs.

Motivate 1 (When this creature enters, you may motivate target creature with less power than this by putting a +1/+1 counter on it.)
When Merthilios' Escort motivates a creature, that creature gains first strike until end of turn.

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.)

Enchant creature
Enchanted creature can't be blocked.
{1}{R}: Enchanted creature gets +1/+0 until end of turn.

Whenever another artifact you control enters, put a +1/+1 counter on Metalwork Machinist.

Artifact spells you cast cost {1} less to cast.
{2}, Sacrifice an artifact: Target creature gains deathtouch until end of turn.

When Miasma Spewer enters, you may sacrifice a permanent. When you do, Miasma Spewer deals 1 damage to each opponent and each creature and planeswalker they control.

Flash

Each player loses 2 life, discards two cards, sacrifices two creatures, then sacrifices two lands.

Choose one—
• Destroy target artifact.
• Target creature gets +4/+4 until end of turn.

Choose one —
• Destroy target artifact.
• You gain 4 life.

Reveal the bottom two cards of your library. You may put one of those cards into your hand. If you do, target creature gets +X/+X until end of turn, where X is that card's mana value.

Until end of turn, target creature gains double strike and damage dealt by it can't be prevented.
Fuse (You may cast one or both halves of this card from your hand.)

At the beginning of your upkeep, you gain 1 life for each creature you control.
{3}{W}: Create a 1/1 white Soldier creature token. Activate only if you have the highest life total among all players.