msem-instigator

At the beginning of each opponent's end step, that player loses 1 life for each creature they control unless they sacrifice a creature. Then they lose 1 life for each card in their hand unless they discard a card.

Trample
When Hunted Sprareos dies, create a 6/6 green Wurm creature token with trample.

Reach
Deploy 3 (As this enters, you may tap any number of other creatures you control with total power 3 or more.)
When Hunting Company enters deployed, destroy target creature with flying.

Erratic (When this creature dies, reveal the top four cards of your library. Put a creature card that costs less than this revealed this way onto the battlefield and the rest on the bottom of your library in any order.)
Ifram's Greenfur must be blocked each combat if able.

Desecrate (When this creature enters, you may sacrifice an artifact or land.)
When Igneous Pulverizer desecrates a permanent, destroy target nonland permanent.

When Ikari-no-Oni enters, other creatures you control get +1/+0 until end of turn.

Vigilance
When Illari, Martyrized Tyrant enters, tap all other nonbasic permanents.
Players can't untap more than one nonbasic permanent during each of their untap steps.
When Illari dies, untap all permanents you control and you gain 5 life.

Flying
When Illuminating Archangel enters, target creature gets +X/+X and gains vigilance and first strike until end of turn, where X is the number of permanents you control that are Angels, Demons, Faeries, and/or Spirits.

Flying
When Imperator Namuzzar enters, search your library for an artifact or enchantment card, reveal it, put it into your hand, then shuffle.
Civilized — Lammasu you control get +2/+2 and have hexproof as long as you control an artifact, a creature, and an enchantment.

Trample
If a creature in Imperial Guardian's pack would deal damage to a permanent or player, it deals twice that much damage instead. (Two or more creatures you control with equal power are in a pack.)

Trample
Art of war — At the beginning of your end step, if Imperial Legion dealt damage to an opponent this turn, put two +1/+1 counters on it.

Motivate 2 (When this creature enters, you may motivate target creature with less power than this by putting two +1/+1 counters on it.)

Reach
{1}, Sacrifice a nonland permanent: Imposing Manticore deals 1 damage to each opponent.

When Incantation Demon enters, return target instant or sorcery card from your graveyard to your hand.
Cycling {2} ({2}, Discard this card: Draw a card.)

This spell costs {1} less to cast for each tapped creature you control.
Whenever Incarnation of Enmity attacks, each other attacking creature gets +1/+0 until end of turn.

Creatures you control attacking causes their death knell to trigger.
Death knell — Indomitable Spirit gets +2/+2 and gains trample until end of turn. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)

{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 Infectious Corpse dies, each player loses 2 life.

Lifelink
Whenever Infectious Ego enters or attacks, exile the top card of target opponent's library. If it's a land card, that player gets a poison counter. You may play that card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast that spell.

Indestructible
{2}{B}, Exile two cards from your graveyard: Each opponent loses 2 life and you gain 2 life.

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

Whenever a creature you control dies, Insidious Terror gets +1/+0 and gains menace until end of turn.

Iron Warden enters with two -1/-1 counters on it.
When Iron Warden dies, you may put its -1/-1 counters on target creature.
{R}: Iron Warden gets +1/+0 until end of turn.

Trample
At the beginning of each combat, you may have Ironhide Bellower deal 3 damage to target creature you control. If you do, Ironhide Bellower gets +3/+0 and can't be blocked by creatures with total power 3 or less until end of turn.

When Ironsmash Wrecker enters, you may destroy target artifact.