msem-instigator

{T}, Sacrifice a land: Destroy target land.

Inquirer, Roaming Rover attacks each combat if able.
Whenever Inquirer deals damage to an opponent, draw a card.

Inquisitor's Chamber enters tapped.
{T}: Add {B}.
{B}{B}, {T}, Sacrifice another permanent: Draw a card.

Whenever Insatiable Abomination or another Horror you control enters, each player mills four cards.
Exile a creature card from your graveyard: Tap target Horror you control. It gains indestructible until end of turn.

Whenever you cast your first instant or sorcery spell each turn, untap equipped creature.
Equip {1}

{4}, {T}: Put a -1/-1 counter on target creature.
{4}, {T}: Remove a -1/-1 counter from target creature.

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

At the beginning of your upkeep, put a lore counter on Inspirational Copse, discard your hand, then draw a card for each lore counter on Inspirational Copse.

Trial 3 (As you cast this spell, an opponent of your choice may pay 3 life. If they don't, they fail the trial.)
When Inspired Trialmaker enters, if the trial was failed, add {R}{W}{B}.

{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.

Scry 3, then reveal the top card of your library. Discard your hand, then draw cards equal to that card's mana value.

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.

Enchant creature
Enchanted creature gets +3/+0 and has haste and menace.

When Insurgent Racketeer enters or dies, you may discard a card. If you do, draw a card.

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

Return up to two target instant and/or sorcery cards from your graveyard to your hand. Exile Intense Revelation.

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.

Until end of turn, gain control of target creature and it gains haste. Untap it.
Fuse (You may cast one or both halves of this card from your hand.)

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.)

This spell costs {1} less to cast for each creature type among creatures you control.
Return up to two target cards from your graveyard to your hand. Exile Intersection of Fates.

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

(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.