msem-instigator

{W}{B}, Shuffle Inexorable Explorer into your library: Return target creature card from your graveyard to the battlefield.
{W}{B}, Sacrifice a creature: Return Inexorable Explorer from your graveyard to the battlefield tapped.

When Inexperienced Martyr dies, each opponent loses 1 life.

When Infamous Bilgecaptain enters, forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.)
Other Pirates you control get +1/+1.
At the beginning of your end step, you may put a Pirate card with mana value less than or equal to the number of artifacts you control from your hand onto the battlefield.

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature gets -1/-1.
Whenever enchanted creature attacks, its controller loses 2 life.

Deathtouch
Whenever Infected Null attacks, each player loses 1 life.

When Infectious Corpse dies, each player loses 2 life.

Whenever Infernal Barrier is dealt damage, it deals 1 damage to each opponent.

Enchant creature
At the beginning of combat on your turn, create a token that's a copy of enchanted creature, except it has haste. Exile that token at the beginning of the next end step.

Infernal Flames deals 3 damage to target player or planeswalker.
Tether (Then if you cast this from your hand, you may exile it tethered to a creature you control. When it dies, you may cast this from exile without paying its mana cost.)

Enchant creature
Enchanted creature gets +3/+0 and has trample.
Madness {1}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Whenever you cast an instant or sorcery spell, Infernal Immolator deals 2 damage to each opponent.

Enchant creature
Enchanted creature has “{R}, {T}: Create an X/1 red Elemental creature token with haste and trample, where X is this creature's power. Exile that token at the beginning of the next end step.”

At the beginning of each end step, if a player lost 5 or more life this turn, create a 5/5 black Demon creature token with flying.

Haste
When Inferno Forerunner enters, you may have target creature gain haste until end of turn.

Inferno Lash deals 2 damage to target creature or planeswalker. When it does, torment that permanent's controller. (They lose 3 life unless they discard a card or sacrifice a nonland permanent.)

Create two 1/1 green Insect creature tokens, then put a +1/+1 counter on target creature you control for each Insect you control.

Whenever a creature you control enters, you may have target creature get +1/+1 and gain flying until end of turn.

Whenever you cast an artifact spell, scry 2.

Search target player's library for a card and exile it. Then that player shuffles.

Whenever a creature you control dies, you may put a +1/+1 counter on target creature you control.

Whenever a land you control enters, you may have target creature get +1/+0 and gain first strike until end of turn.

Each opponent plays with the top card of their library revealed.
During each of your turns, you may play one card from the top of an opponents' library, and you may spend mana as though it were mana of any color to cast that spell.

Whenever Infiltrator of the Anomalous deals combat damage to a player, add {R}. Until end of turn, you don't lose this mana as steps and phases end.

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature can't be blocked.
{1}{U}: Enchanted creature gains hexproof until end of turn.

At the beginning of your upkeep, discard a card or sacrifice Infinite Suspension.
Creatures you control get +1/+1 and have flying.