msem-instigator

When Ideologize enters, exile target creature an opponent controls and each other permanent with the same name that player controls. When Ideologize is no longer on the battlefield, return a card exiled with it to the battlefield under its owner's control.

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.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Idleglen Instructor enters, draw a card, then discard a card.

Each nontoken land you control has all activated abilities of each other land on the battlefield.
When Idyll leaves the battlefield, until the end of your next turn, you gain “Each nontoken land you control has all activated abilities of each other land on the battlefield.”

Search your library for an enchantment card, reveal it, put it into your hand, then shuffle.

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.

Augmented — When you cast If Memory Serves, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, copy it twice. You may choose new targets for the copies.
Return target permanent card with mana value 3 or less from your graveyard to the battlefield. Exile If Memory Serves.

{G}{U}{R}, Discard a card named Ifram, God of Chaos: Ifram gains indestructible and becomes a God creature in addition to its other types.
Whenever Ifram enters or attacks, choose target non-God permanent. Its owner shuffles it into their library, then its controller reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

As an additional cost to cast this spell, pay X life.
Ignition Ritual deals X damage to each creature and each planeswalker.

You get a fuse counter, then Ignition Sequence deals X damage to any target, where X is 2 plus the number of fuse counters you have.

Sabotage — Whenever an opponent or permanent an opponent controls becomes the target of a spell you control, Iken Troubleshooter deals 2 damage to each opponent.

You have no maximum hand size.
At the beginning of your upkeep, draw a card.
At the beginning of your end step, you lose 1 life for each card in your hand.

When Ill-Fated Seer enters, each player sacrifices a creature. If they can't, Ill-Fated Seer deals 3 damage to them.
Revive {2}{B}{R} ({2}{B}{R}, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost. Activate only as a sorcery.)

Flying
Illuminated Firebird can't block.
Foresight — Whenever you draw your second card each turn, return Illuminated Firebird from your graveyard to the battlefield.

You may have Illusion of the Div enter as a copy of any creature you control except it has “{G}{U}{B}, Discard a card: Create a tapped token that is a copy of this creature.”

Each opponent sacrifices a creature or planeswalker. If you own a foretold card in exile, you gain 4 life.

Destroy target artifact.
Reprise {R} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Whenever a face-down creature you control attacks, defending player loses 1 life.
{2}, Discard a card: Manifest the bottom card of your library. Activate only once each turn. (To manifest a card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

Exile target creature card from a graveyard. Create a token that's a copy of that creature, except it's a colorless artifact. (It's not a creature.)

Enchant creature
When Imperative Blessing enters, draw a card.
Enchanted creature gets +2/+2.

When Imperfect Stone enters, mill three cards.
{T}: Add one mana of any color.

When Imperial Artisan enters, draw three cards, then put two cards from your hand on top of your library in any order.

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.

When Imperial Diplomats enters, if it's not a token, create a token that's a copy of it, except it has no mana cost.
{T}, Tap an untapped creature you control: Draw a card, then discard a card.

First strike
When Imperial Dragoon enters, target creature gets +2/+0 until end of turn.