msem-instigator

Whenever you make first contact, Hotshot Renegade deals 2 damage to up to one target creature or planeswalker. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)

Flying
When Hoverbike Courier enters, you may reappropriate. If you do, draw a card. (To reappropriate, exile exactly two cards from your hand and/or graveyard.)

When Howler Sheriff enters, gain control of up to one target creature with a bounty counter on it until end of turn. Untap that creature. It gains haste until end of turn.

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

Other untapped creatures you control have indestructible.
{2}{G}{W}: Target creature gains vigilance until end of turn.

When Humored Outlaw enters, choose one —
• Put a +1/+1 counter on Humored Outlaw. (Assassins, Mercenaries, Pirates, Rogues, and Warlocks are outlaws.)
• Destroy target artifact or enchantment.

Menace
Other Zombies you control get +1/+1.
Whenever a Zombie you control dies, each opponent loses 1 life.

You may cast Hunter of the Moon-Serpent from your graveyard as long as you gained life this turn.

Flying, vigilance

Whenever you cast a noncreature spell, Hutao's Wardens deals 2 damage to each opponent. Then if that spell was an enchantment, scry 2.

Flash
When Icecrowned Fox enters, you may return target spell or permanent to its owner's hand.
Each untapped creature you control has “Ward—Discard a card.” (Whenever it becomes the target of a spell or ability an opponent controls, counter it unless that player discards a card.)

You may have Icefang Wurm assign its combat damage as though it weren't blocked.
{4}{G}{G}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)

Each nontoken land you control has all activated abilities of each other land on the battlefield.
When Idyll leaves the battlefield, until the end of your next turn, you gain “Each nontoken land you control has all activated abilities of each other land on the battlefield.”

Sabotage — Whenever an opponent or permanent an opponent controls becomes the target of a spell you control, Iken Troubleshooter deals 2 damage to each opponent.

Trample
Whenever another nontoken creature you control dies, you may return it to the battlefield. It becomes an Aura enchantment with enchant creature you control and “Enchanted creature gets +X/+X, where X is this Aura's mana value.”

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

When Ill-Fated Seer enters, each player sacrifices a creature. If they can't, Ill-Fated Seer deals 3 damage to them.
Revive {2}{B}{R} ({2}{B}{R}, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost. Activate only as a sorcery.)

Whenever Illumination Savant attacks, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Put a +1/+1 counter on each artifact creature and enchantment creature you control.

Flash
Trample

{G}: Exile target card from a graveyard. If a creature card with flying is exiled this way, put a flying counter on Illustrious Qilin. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, reach, trample, and vigilance.

Whenever Imisti, Elven Insurgent attacks, mill two cards. When you do, you may return target land card from your graveyard to your hand.
{X}{B}{G}: If Imisti has no +1/+1 counters on it, put X +1/+1 counters on Imisti. Activate only as a sorcery.

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

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
{1}, Sacrifice another creature: Imperious Aristocrat gains indestructible until end of turn. If you're in a renaissance, each opponent loses 2 life and you gain 2 life.

Whenever Impetuous Impetus deals combat damage to a player, you may sacrifice a land. If you do, Impetuous Impetus deals 3 damage to that player.

Flash
First strike
When Imposing Databdara enters, return each other creature with toughness less than or equal to the number of Satrapies you control to their owners' hands.