msem-instigator

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

Choose one or both —
• Create two 1/1 white Soldier creature tokens. They gain haste until end of turn.
• Create an 8/0 green Scorpion creature token with trample.

Target player sacrifices a nontoken creature and mills three cards.

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.

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.

Draw X cards.
Flashback—{U}{U}{U}, Sacrifice X permanents. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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.)

Draw a card for each Avatar you control.

Destroy target artifact or enchantment. You gain 4 life.

Enchant creature
Enchanted creature can't attack or block, can't be sacrificed, and its activated abilities can't be activated.

When Ion Field enters, target player creates two 1/1 red Elemental creature tokens.
Whenever you cast an instant or sorcery spell that targets only one target, you may pay {1}{R}{R} and sacrifice Ion Field. If you do, copy that spell for each other target it could target. Each copy targets a different one of those targets.

{T}: Add {G}.
{T}: Add one mana of any color. Activate only if you control another Dryad.

Target creature you control deals damage equal to its power to another target creature.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

First strike
Whenever you cast an artifact or enchantment spell, put a +1/+1 counter on Ironclad Infantry.

When Ironeyes Desperado is exiled from your library, you may pay {R}. If you do, cast it without paying its mana cost.
Haste

When Irticull's Vanguard enters, exile target nonland permanent an opponent controls until Irticull's Vanguard leaves the battlefield.
Reprocess {1}{W}{W}{W} (Cast a copy of this from your graveyard by exiling it and paying {1}{W}{W}{W}. Spend only mana from differently named sources this way.)

Flying
Morph {3}{U}{R} (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 Punishment is turned face up, put a +1/+1 counter on it, then untap another target tapped creature. Ishim of Punishment deals 3 damage to that creature.

Flying
Morph {3}{G}{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 Tempest is turned face up, put a +1/+1 counter on it, draw three cards, then discard two cards.

As Isochron Wand enters, you may exile an instant or sorcery card with mana value 1 from your hand.
At the beginning of your upkeep, you may copy the exiled card. If you do, you may cast the copy without paying its mana cost if the spell's mana value is 1.

Counter target creature spell or target spell that targets a creature an opponent controls.

Eureka! (At the beginning of each end step, you get a research counter if you cast a spell this turn. Then if you have eight or more research counters, remove them and create a Masterpiece token of your choice.)
Whenever you cast a noncreature spell, create a 1/1 colorless Construct artifact creature token.