msem-instigator

Whenever Imako, Ninefingers becomes tapped, exile the top three cards of target opponent's library face down.
You may look at cards exiled with Imako.
Sacrifice Imako: Turn all cards exiled with it face up. Exile all cards with those names from your opponent's graveyards.

Whenever Imisti, Elven Insurgent attacks, mill two cards. When you do, you may return target land card from your graveyard to your hand.
{X}{B}{G}: If Imisti has no +1/+1 counters on it, put X +1/+1 counters on Imisti. Activate only as a sorcery.

Flying
When Imperator Namuzzar enters, search your library for an artifact or enchantment card, reveal it, put it into your hand, then shuffle.
Civilized — Lammasu you control get +2/+2 and have hexproof as long as you control an artifact, a creature, and an enchantment.

First strike, vigilance
Partner with Commander Hyctaleon (When this creature enters, target player may put Commander Hyctaleon into their hand from their library, then shuffle.)
At the beginning of your upkeep, you may search your library for a Soldier card, reveal it, put it into your hand, then shuffle.

Flying
When Ineptitude enters, untap target creature and gain control of it until end of turn. Put three stun counters on that creature. It gets +3/+3 and gains haste until end of turn.

Hexproof
Whenever another creature you control becomes the target of a spell an opponent controls, you may submerge that creature. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)
{1}{U}{U}: Turn target face-down creature you control face up.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
[+1]: Scry 1. If you're in a renaissance, draw a card.
[–2]: Return target nonland permanent to its owner's hand if its mana value is 3 or less or if you're in a renaissance.
[–6]: Create two 8/8 blue Kraken creature tokens. If you're in a renaissance, take an extra turn after this one.

[+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.

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.

{T}: Add {U} or {R}. Spend this mana only to cast an instant, sorcery, or Wizard spell.
Whenever you cast your second spell each turn, untap Innova.

{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.

[+1]: Each opponent puts a -1/-1 counter on a creature they control.
[–1]: Exile target card in a graveyard. You gain life equal to its mana value.
[–6]: Choose a number. You draw that many cards and you lose that much life.

[+1]: Create a tapped 3/3 black Crocodile creature token with menace.
[–1]: You may cast a copy of Size Up.
[–7]: Each land you control becomes a 3/3 Crocodile creature and gains menace and haste until end of turn.

Flash
Deathtouch, lifelink
Whenever Irika, Wielder of Secrets deals combat damage to a player, you may pay {U/B}. If you do, you draw a card and you lose 1 life.

Indestructible
As long as your devotion to red and white is less than seven, Iroas isn't a creature.
Other creatures you control have first strike.
Whenever you attack for the first time each turn, untap all other creatures you control. After this phase, there is an additional combat phase.

Flash
As long as Iroshi entered this turn, you may activate their loyalty abilities any time you could cast an instant.
[+1]: You may return a creature you control to its owner's hand. If you do, draw a card.
[–1]: Create a 2/2 green Ninja creature token.
[–2]: Target creature you control deals damage equal to its power to target creature or planeswalker.

Whenever you cast a noncreature spell, scry 1.
{3}{U}, Exile an instant or sorcery card from your graveyard: Draw a card.

Whenever you cast a creature or planeswalker spell, if mana produced by a nonland permanent was spent to cast it, it gains trample and haste until end of turn.
{T}: Add {R} or {G}.

Tap an untapped creature you control: Put a loyalty counter on Ivenge, False God. Activate only once each turn.
[+1]: Exile up to one target non-Plains permanent. At the beginning of that card's owner's next upkeep, return it to the battlefield under their control.
[–2]: Exile target nonland permanent an opponent controls. They create a Plains token. (It's a basic land with “{T}: Add {W}.”)
[–10]: Exile all permanents your opponents control. For each permanent exiled this way, its controller creates a colorless Plains basic land token.

[+2]: You may draw a card. If you don't, create a Treasure token. Repeat this process once.
[0]: Iviana deals X damage to each creature you don't control, where X is 2 plus twice the number of Dragons you control.
[–3]: Create a 5/5 red Dragon creature token with flying and haste.

Wildcast — When Ivier, Soul of the Woods enters, return target monocolored creature card from your graveyard to your hand. If mana from a nonland source was spent to cast Ivier, return that card to the battlefield instead.

Improve {1} ({1}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
Whenever Ivy Kissinger, Sharpshooter attacks, choose a creature you control. For each kind of counter among creatures you control, you may put a counter of that kind on the chosen creature.

{T}: Izahl, the Stormbringer deals 1 damage to any target.
Whenever you cast a noncreature spell, you may untap target creature you control.

[+2]: Sacrifice a creature. If you do, you may draw two cards.
[–1]: Gain control of target creature for as long as you control Jachsechep, God's Wife.
[–10]: You get an emblem with “Whenever a creature enters under an opponent's control, gain control of it.”