msem-instigator

Deploy 4 (As this enters, you may tap any number of other creatures you control with total power 4 or more.)
When Mechanical Tactician enters deployed, tap up to two target creatures an opponent controls. Those creatures don't untap during their controller's next untap step.

Each opponent loses 2 life and you gain 2 life. You mill two cards.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Untap all nonland permanents you control.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

{1}{U}: Mercurial Merfolk gets +2/-2 until end of turn.
When Mercurial Merfolk dies, draw a card.

Enchant creature or artifact
When Meticulous Process enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
Enchanted permanent doesn't untap during its controller's untap step.

Whenever you activate your first nonmana activated ability each turn, create a tapped 1/1 white Spirit creature token with flying.
{4}{W}{U}: You gain 1 life and draw a card.

Flying
When Midnight Visitor enters, you may return target creature to its owner's hand.

When Militia Surgeon enters the battlefield, you gain 2 life.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Sacrifice Misleading Wisp:
Counter target spell unless its controller pays {1}.

[+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.)

Morningstar Blaze deals X damage divided as you choose among one or two targets.

Whenever Mortified Medium or another creature enters the battlefield, you gain 1 life.
As long as you have at least 10 life more than your starting life total, Mortified Medium gets +4/+4 and has flying.

Players can't get counters.
Counters can't be put on permanents.

As an additional cost to cast this spell, pay {2} or put a -1/-1 counter on a creature you control.
Munitions Explosion deals 3 damage to any target.

Whenever Mysteries of Life enters or you create a token, choose one that hasn't been chosen this turn —
• You gain 2 life.
• Draw a card, then discard a card.
• You may tap or untap target permanent.

When Naive Apprentice enters, each player creates a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
As long as an opponent controls an artifact, Naive Apprentice gets +2/+0.

This spell can't be countered.
Creatures you control have ward {2}. (Whenever one becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
When Natural Philosopher enters, you gain 2 life for each creature you control with power 4 or greater.

Harmony — You gain 2 life.
When New Alores Fiddler enters the battlefield, harmonize. (Trigger up to one harmony of one permanent you control.)

When Night Howlers enters the battlefield, target opponent reveals three cards from their hand and you choose one of them. Exile that card until Night Howlers leaves the battlefield.

When Night Shepherd enters the battlefield, return a creature you control to its owner's hand.

Choose X. Target player reveals their hand and discards all nonland cards with mana value X.

Wither (This deals damage to creatures in the form of -1/-1 counters.)
{1}{B}: Return Noonfiend from your graveyard to your hand.