msem-instigator

Whenever you cast a noncreature spell, upgrade Indecisive Sorceress. When you can't, remove all counters from it and it deals damage to any target equal to the number of counters removed this way.
• +1/+1
• Flying
• First strike

This spell costs {X} less to cast, where X is the greatest power among creatures you control.
{1}: Target creature in Indomitable Anchorite's pack gains indestructible until end of turn. (Two or more creatures you control with equal power are in a pack.)

Creatures you control attacking causes their death knell to trigger.
Death knell — Indomitable Spirit gets +2/+2 and gains trample until end of turn. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)

Target creature gets -1/-1 until end of turn.
Threshold — You may destroy that creature instead if seven or more cards are in your graveyard.

This spell costs {1} less to cast for each creature and/or planeswalker card in your graveyard.
Return target creature or planeswalker card from your graveyard to the battlefield.

Enchant opponent
Creatures enchanted player controls get -2/-2.
Whenever enchanted player casts a noncreature spell, they lose 2 life and you gain 2 life.

When Infamous Bilgecaptain enters, forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.)
Other Pirates you control get +1/+1.
At the beginning of your end step, you may put a Pirate card with mana value less than or equal to the number of artifacts you control from your hand onto the battlefield.

Lifelink
Whenever Infectious Ego enters or attacks, exile the top card of target opponent's library. If it's a land card, that player gets a poison counter. You may play that card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast that spell.

Enchant creature
At the beginning of combat on your turn, create a token that's a copy of enchanted creature, except it has haste. Exile that token at the beginning of the next end step.

Enchant creature
Enchanted creature has “{R}, {T}: Create an X/1 red Elemental creature token with haste and trample, where X is this creature's power. Exile that token at the beginning of the next end step.”

Inferno Lash deals 2 damage to target creature or planeswalker. When it does, torment that permanent's controller. (They lose 3 life unless they discard a card or sacrifice a nonland permanent.)

Search target player's library for a card and exile it. Then that player shuffles.

Each opponent plays with the top card of their library revealed.
During each of your turns, you may play one card from the top of an opponents' library, and you may spend mana as though it were mana of any color to cast that spell.

At the beginning of your end step, shuffle your hand and graveyard into your library, then draw seven cards.

Once each turn, when a player casts a spell, you may choose two target players. Each of those players exiles cards from the top of their library until they exile a nonland card with mana value less than that spell's. They may cast those cards without paying their mana cost. Then they put the rest of the exiled cards on the bottom of their library in a random order. (The active player puts their spell on the stack first.)

{3}, {T}: Put Ing'Wei's Crystal Top on top of your library. Scry 3, then draw a card.

[+1]: Look at the top two cards of your library. Put one of them into your hand and the other into your graveyard.
[–2]: Return target card from your graveyard to the battlefield face down.
[–6]: Turn any number of face-up nonland permanents of your choice face down.

Flying, prowess
Whenever you cast a noncreature spell, untap Ingenious Trickster.

Whenever Inishtu, Desert Healer enters or attacks, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
At the beginning of your upkeep, if seven or more cards are in your graveyard, you may transform Inishtu.

Indestructible
{2}{B}, Exile two cards from your graveyard: Each opponent loses 2 life and you gain 2 life.

Whenever Inkwell Daggers enters or attacks, proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

Whenever a creature you control enters for the second time each turn, it gains haste until end of turn. You may have it get +1/+1 until end of turn.

{T}, Sacrifice a land: Destroy target land.

Inquirer, Roaming Rover attacks each combat if able.
Whenever Inquirer deals damage to an opponent, draw a card.

Whenever Inquisitive Guardian deals combat damage to an opponent, you may exile a nonland card from your graveyard. If you do, draw a card.
{U}: Inquisitive Guardian gains flying until end of turn.