msem-instigator

{T}: Add {U} or {R}. Spend this mana only to cast an instant, sorcery, or Wizard spell.
Whenever you cast your second spell each turn, untap Innova.

Whenever a creature you control enters for the second time each turn, it gains haste until end of turn. You may have it get +1/+1 until end of turn.

Vigilance
When Inquisitive Student enters, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

{3}{B}, {T}: Choose a card name. Target player reveals cards from the top of their library until they reveal a card with the chosen name. If they do, put the revealed cards into their graveyard. Otherwise, they shuffle their library.

Whenever Insatiable Student attacks, you may sacrifice an artifact. When you do, tap target creature an opponent controls.

Insightful Blow deals 3 damage to target attacking or blocking creature. Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

You may have Insipid Metamorph enter as a copy of any other creature on the battlefield, except it's 1/1.

{1}{W}, {T}: Tap target creature.
Put a -1/-1 counter on Insistent Ingenue: Untap Insistent Ingenue.

Draw a card.
Compose (Then if you cast this from your hand, exile it and create a Saga token with “r3—You may cast a copy of this card from exile without paying its mana cost.”)

Enchant creature
Enchanted creature gets +1/+2.
Whenever enchanted creature attacks, scry 1.

When Inspired Blade enters, if you control another Warrior, draw a card.

{1}{W}, {T}: Other creatures you control get +1/+1 until end of turn.

{2}, {T}: Put a +1/+1 counter on target creature you control.
{2}, {T}, Sacrifice Inspiring Effigy: Put a +1/+1 counter on each creature you control.

Whenever Inspiring Tactician or another permanent you control becomes the target of a spell or ability you don't control, amass Soldiers 1. (Put a +1/+1 counter on an Army you control. It's also a Soldier. If you don't control one, create an 0/0 black Soldier Army creature token first.)

Inspirited Duelist has double strike as long as it has a +1/+1 counter on it.

Whenever you cast or copy an instant or sorcery spell this turn, Instant of Brilliance deals 1 damage to each opponent.
Copy target instant or sorcery spell you control. You may choose new targets for the copy.

At the beginning of your upkeep, reveal the top card of your library. Any opponent may have Insurgent Ballads deal damage to them equal to that card's mana value. If a player does, put that card on the bottom of your library. Otherwise, put it into your hand.

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.

Exile the top card of your library. Until end of turn, you may play that card. If that card is an instant or sorcery card, it costs {2} less to cast this turn.

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.

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

Search your library for a Forest card, put it onto the battlefield, then shuffle.