msem-instigator

Flying, trample, haste
Whenever you activate an ability of a nonland permanent, you may have Ilieth, Transcendent deal 2 damage to target creature.
{2}{R}: Creatures you control get +2/+0 until end of turn.

Vigilance
When Illari, Martyrized Tyrant enters, tap all other nonbasic permanents.
Players can't untap more than one nonbasic permanent during each of their untap steps.
When Illari dies, untap all permanents you control and you gain 5 life.

Hexproof, indestructible
You don't lose the game for having 0 or less life.
For each 1 life you would lose while you have 0 or less life, instead put a -1/-1 counter on a creature you control with toughness 1 or greater.

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.

At the beginning of your upkeep, scry 2.
Reveal the top card of your library: If a creature card with flying was revealed this way, Imperial Chimera gains flying until end of turn. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, reach, trample, and vigilance.

Flash
You may cast this spell from your graveyard, but not from anywhere else. When you do, destroy target permanent.

Reach
Imperious Ram can't be blocked by more than one creature.

Lionize {1}{U} ({1}{U}, Exile this card from your hand: Put a +1/+1 counter on target creature and it gains the following ability until end of turn. You may cast this card on a later turn from exile.)
Hexproof

Flash
Defender
When Imposing Barricade enters, target creature doesn't untap during its controller's untap step for as long as you control Imposing Barricade.

Defender

Motivate 2 (When this creature enters, you may motivate target creature with less power than this by putting two +1/+1 counters on it.)

Reach
{1}, Sacrifice a nonland permanent: Imposing Manticore deals 1 damage to each opponent.

Flying
When Imposing Sphinx enters, exile target nonland permanent an opponent controls until Imposing Sphinx leaves the battlefield.
At the beginning of your end step, if you gained life this turn, you may exile Imposing Sphinx, then return it to the battlefield under your control.

This spell costs {1} less to cast for each tapped creature you control.
Whenever Incarnation of Enmity attacks, each other attacking creature gets +1/+0 until end of turn.

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.)

Menace
Ward—Pay 3 life.
When Infernal Direwolf enters, it fights up to one target creature an opponent controls. Excess damage Infernal Direwolf deals this way is dealt to that creature's controller instead.

When Influential Wildborn enters, proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)
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.)

When Ingredient Scroungers enters, if you control a creature with deathtouch, return target permanent card from your graveyard to your hand.

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

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
{U}{R}: Target creature without prowess gains prowess until end of turn. Activate only if Intelligence is in your graveyard.

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.

Reach
When Ironclad Sentry enters, you may return target permanent card not named Ironclad Sentry from your graveyard to your hand.

Flying
Morph {1}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Ishim of the Mists is turned face up, turn all other face-up creature you control face down.

When Isle Conservator enters, if you control a legendary creature, submerge target creature an opponent controls. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)