msem-instigator

Whenever you cast a spell, you may cast a spell from your hand with lesser mana value without paying its mana cost.
You can't cast more than one spell of each card type each turn.

When Iekin's Portal enters, look at the top five cards of your library. Put one into your hand and the rest into your graveyard.
{1}{U}{U}: Transform Iekin's Portal. Activate only if your fealty to Islands is five or greater.

Ward—Pay 3 life.
Igniderm enters with three ignition counters on it.
At the beginning of your upkeep, remove an ignition counter from Igniderm. If you can't, sacrifice it.

At the beginning of combat on your turn, gain control of another target permanent until end of turn. Untap that permanent. It gains haste until end of turn.
Fleeting {2}{R}{R} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

When Ikari-no-Oni enters, other creatures you control get +1/+0 until end of turn.

Flying, hexproof, haste
Blue permanents you control have hexproof.
Whenever you activate an ability of a red permanent, you may copy that ability. If you do, choose new targets for the copy.

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.

Each player exiles up to X cards from their graveyard. Then each player loses life, discards cards and sacrifice creatures equal to X minus the number of cards that player exiled this way.

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.

Whenever Illumination Savant attacks, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Put a +1/+1 counter on each artifact creature and enchantment creature you control.

Flash
Whenever you make first contact, you may put a card you own from outside the game into your hand. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)

You may have Imitator of Success enter as a copy of any creature on the battlefield, except it has no mana cost and base power and toughness 1/1 if it's a token.
Successor {1}{U}{U} ({1}{U}{U}, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost and base power and toughness 1/1. Succeed 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.

Draw three cards.
Lifecycle {3} ({3}, Discard this card: Create two tapped 1/1 colorless Elemental creature tokens.)

All creatures get -2/-2 until end of turn.
Civilized — Instead only creatures your opponents control get -2/-2 until end of turn if you control an artifact, a creature, and an enchantment.

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.

Trample
If a creature in Imperial Guardian's pack would deal damage to a permanent or player, it deals twice that much damage instead. (Two or more creatures you control with equal power are in a pack.)

Trample
Art of war — At the beginning of your end step, if Imperial Legion dealt damage to an opponent this turn, put two +1/+1 counters on it.

Whenever Impetuous Impetus deals combat damage to a player, you may sacrifice a land. If you do, Impetuous Impetus deals 3 damage to that player.

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

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

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 {2} less to cast if there's a storied card in your graveyard. (Enchantments and legendary cards are storied.)
Search your library for a storied card, reveal it, put it into your hand, then shuffle.

Trial 4 (As you cast this spell, an opponent of your choice may pay 4 life. If they don't, they fail the trial.)
Search your library for an Angel card, reveal it, put it into your hand, then shuffle. If the trial was failed, non-Angel, non-God creatures can't attack or block until your next turn.