msem-instigator

Equipped creature gets +1/+2.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Whenever you cast your second spell each turn, scry 2.

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.

Creatures you control have haste.
Whenever you attack, put a charge counter on Intensifying Luminescence.
At the beginning of your first main phase, add {R} for each charge counter on Intensifying Luminescence.

Whenever a +1/+1 counter is put on a creature you control, scry 1.
Each creature you control with a +1/+1 counter on it has lifelink.

Flying
{1}{W}: Exile target artifact you control. Return that card to the battlefield under your control at the beginning of the next end step.

Interan Soothsayer gets +1/+1 for each other green creature you control.
{G}, {T}: Put a +1/+1 counter on target green creature.

({T}: Add {U}.)
Interlocked Waterways enters tapped.
{U}, {T}, Reveal a blue card from your hand: Untap target creature.

Whenever a creature enters, it deals damage equal to its power to any target of its controller's choice.
When Interplanar Raid enters, you may aetherize target creature you control. (To aetherize, create a token that's a copy of it, then exile that token.)

{T}: Add {C}.
{1}, {T}: Add two mana of different colors. Activate only if you control five or more lands.

Flying, ward {2}
Intisuyu's Masterpiece gets +X/+X, where X is the number of artifacts and/or enchantments you control.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
Put a +1/+1 counter on target creature you control.
Double the number of counters on target creature you control.
​

Whenever you tap a land for mana, add one mana of any type that land produced.
Sacrifice Into Strange Territories: Untap up to two lands.

If a card would be put into your graveyard from anywhere, exile it instead.
If you would draw a card, return two cards from your graveyard to your hand instead. If you can't, you lose the game.

When Into the Lion's Den enters, target opponent reveals their hand. You choose a nonland card from it and exile that card until Into the Lion's Den leaves the battlefield.

When Into the Unknown enters, create two 1/1 Scout creature tokens that are all colors.
Whenever a land you control enters, if it doesn't have the same name as another land you control, put a +1/+1 counter on each creature you control.

Flying
When Intrepid enters, search your library for a land card, reveal it, put it into your hand, then shuffle.
Wanderlust — {0}: Intrepid becomes an artifact creature until end of turn. Activate only if you control four or more differently named lands.

At the beginning of combat on your turn, create a 1/1 blue and red Pirate creature token with haste. That token attacks this combat if able.
Whenever Intrepid Captain attacks, other attacking Pirates you control get +1/+0 until end of turn.

Improve {W} ({W}: 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 one or more embattled creatures you control attack, create a 1/1 white Cleric creature token with lifelink. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

When Intrepid Shieldmate enters, target creature gets +1/+1 until end of turn.

Flash
When Intrepid Shooter enters, it deals 2 damage to target attacking creature.

Advance {4}{R} (Cast this for {4}{R} to advance it as it enters. {4}{R}: Advance this as a sorcery.)
Whenever Intruder Drone advances, exile the top card of your library. You may cast a spell exiled with Intruder Drone with mana value 3 or less without paying its mana cost.

({T}: Add {U}.)
Inundated Sanctuary enters tapped with two sanctum counters on it.
{T}, Remove a sanctum counter from Inundated Sanctuary: Add {W} or {B}.

At the beginning of your upkeep, rouse 1. Then if you control a creature with power 5 or greater, put a +1/+1 counter on each creature you control. (Put a +1/+1 counter on a permanent you control. If it isn't a creature, tap it and it becomes a 0/0 creature in addition to its other types.)

Inviolable Realms enters tapped unless you control two or more other lands.
{T}: Add {U}.
{T}, Pay 1 life: Add {W} or {B}.