msem-instigator

Whenever another Knight or Soldier you control enters, target player loses 1 life.

When Horizon Treader enters, you may exile target enchantment you control. Return that card to the battlefield under your control at the beginning of the next end step.

Whenever this creature enters or attacks, you may put a creature card with mana value 2 or less from your hand onto the battlefield. If you do, draw a card. Sacrifice that creature at the beginning of the next end step.
If a creature would enter under your control during combat on your turn, that creature enters tapped and attacking.

Menace
Whenever Hui Zhou, the Dark Visage perseveres, you may destroy another target legendary creature. (A creature perseveres when it survives damage.)

Lifelink
Whenever another creature you control enters, Hungering Cult deals 3 damage to it.

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

Hurtling Swine attacks each combat if able.

Flying, vigilance

Flying, vigilance, lifelink
Idyllic Pegasus gets +1/+0 for each artifact and/or enchantment you control.

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

{T}, Sacrifice Ilhus, Knight of Zarad: Destroy all creatures.

Flying
Whenever Immaculate Clouddasher attacks, up to three target creatures gain flying until end of turn.

Defender
When Immured Fiend enters, target opponent discards two cards.

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.

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.)

Advance {3}{W}{W} (Cast this for {3}{W}{W} to advance it as it enters. {3}{W}{W}: Advance this as a sorcery.)
Whenever Inconspicuous Loxodon advances, search your library for an Equipment card, put it onto the battlefield, then shuffle.
As long as Inconspicuous Loxodon is enchanted or equipped, he's a 5/5 legendary Elephant Rogue named Agent E.

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.)

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.

When Inner-Eye Obscurist enters, return each other creature that isn't in Inner-Eye Obscurist's pack to their owners' hand. (Two or more creatures you control with equal power are in a pack.)

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

Whenever you cast your second spell each turn, scry 2.

Flying, lifelink
Whenever another creature you control attacks, until end of turn, that creature gets +2/+0 if it's red, +0/+2 if it's green, gains lifelink if it's white, and gains flying it if it's blue.

{T}: Add {G}.
{T}: Add one mana of any color. Activate only if you control another Dryad.