msem-instigator

As an additional cost to cast this spell, sacrifice a creature.
Enchant creature
Enchanted creature gets +4/+4, has flying, and is a Demon in addition to its other types.

Put a +1/+1 counter on target creature.
Inscribe {2}{W} ({2}{W}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Target creature gains lifelink until end of turn. Untap that creature.
Inscribe {1}{W} ({1}{W}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Target creature gets +1/+3 until end of turn. (Then exile this card. You may cast the creature later from exile.)

Draw a card.
Inscribe {1}{U} ({1}{U}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Creatures can't attack you or planeswalkers you control unless their controller pays {X} for each of those creatures, where X is the number of attacking creatures.

Mill three cards, then you may return a creature or land card from your graveyard to your hand.

[+1]: Each opponent puts a -1/-1 counter on a creature they control.
[–1]: Exile target card in a graveyard. You gain life equal to its mana value.
[–6]: Choose a number. You draw that many cards and you lose that much life.

{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.

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

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature gets +2/+3 and has lifelink.

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}.

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.”)

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.

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.

Escalate {R} (Pay this cost for each mode chosen beyond the first.)
Choose one or both —
• Untap all creatures you control.
• Take an extra turn after this one. Skip the untap step of that turn. Exile Inspire Actuality.

Creatures you control get +2/+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.

Harvest (You may tap any number of creatures you control as you cast this spell. If you do, reduce this spell's mana cost by their total power.)
Draw three cards.

Enchant creature
Whenever enchanted creature attacks, other creatures you control get +1/+2 until end of turn.

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

Creatures you control get +1/+1 until end of turn. Token creatures you control get an additional +1/+1 until end of turn.