msem-instigator

Deathtouch
Whenever a creature an opponent owns dies, exile the top two cards of that player's library face down. For as long as those cards remain exiled, you may look at them, you may cast them, and you may spend mana as though it were mana of any type to cast them.

Whenever Hadik's Striker is dealt damage, you gain that much life.

Haste
{2}{W}, {T}: Hair-Trigger Marshall deals 2 damage to target blocking creature.

Lifelink
Whenever you cast a spell with mana value 2 or less, put a +1/+1 counter on Hallowed Moon Sentinel.

Flying
When Hallowed Perspective enters, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
You may exert Hallowed Perspective as it attacks. When you do, until your next turn, you may cast spells as though they had flash. (An exerted creature won't untap during your next untap step.)

When Hand of Dominion enters, tap target creature an opponent controls. It doesn't untap during its controller's next untap step.
At the beginning of your upkeep, if your fealty to Islands is five or greater, transform Hand of Dominion. (Each Island you control counts towards your fealty to Islands.)

Menace (This creature can't be blocked except by two or more creatures.)
Infiltrate (Whenever one or more attacking creatures you control aren't blocked, this creature gets +1/+1 until end of turn.)

Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{U}, {T}: You may tap or untap target Human.

Flying, trample
Harbinger of Falling Skies enters with X +1/+1 counters on it.
Whenever Harbinger of Falling Skies attacks, you may remove a +1/+1 counter from it. If you do, draw a card.

{U}, Give yourself a lore counter: Scry 1. This ability costs {2} more to activate for each lore counter you have.
{6}{U}, Remove three lore counters from yourself, Sacrifice Harbinger of Giradrus: Draw seven cards, then create two 4/4 red Dragon creature tokens with flying.

When Harbinger of Growth enters, create a 1/1 green Saproling creature token.
{1}{G}, Sacrifice Harbinger of Growth: Populate. (Create a token that's a copy of a creature token you control.)

When Hardlight Visionary enters, create a Function token with “Until end of turn, target creature becomes a 5/5 Dragon and gains flying.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Double strike
When this creature enters, mill four cards. Put a creature card with power 2 or less from among the cards milled this way into your hand.

Whenever you cast an enchantment spell, you may pay {W}. If you do, put a +1/+1 counter on target creature.

Whenever another nontoken permanent you control enters, create a Food token.
At the beginning of each end step, put X +1/+1 counters on up to one target creature, where X is the amount of life you've gained this turn.

{1}, {T}, Move a -1/-1 counter from another creature onto Harried Apothecary: Each opponent loses 1 life and you gain that much life.

When a creature you control scavenges Harvest Reaper, search your library for a colorless card, reveal it, put it into your hand, then shuffle.
Scavenge {4} ({4}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

Whenever another creature you control enters, you may gain 1 life.
Whenever a creature enters under an opponent's control, you may have that player lose 1 life.

Whenever you cast a spell during an opponent's turn, Haughty Priest deals 1 damage to that player.

When Haunted Hermit enters, choose one —
• Put a +1/+1 counter on Haunted Hermit.
• Create a 1/1 white Spirit creature token with flying.

Whenever Haunted Prodigy attacks, you may tap target creature.
Unveil {2}{W}{U} ({2}{W}{U}: Transform this. Unveil only as a sorcery.)

Whenever you cast a black spell, you may exile target creature. Return that card to the battlefield under its owner's control at the beginning of the next end step.
Whenever you cast a red spell, you may have Haunted Sunseeker deal 1 damage to each creature.

Vigilance
At the beginning of your end step, if you control two or more Spirits and/or creatures with flying, transform Haunted Waif.

Lifelink
Whenever you sacrifice a creature, you gain life equal to its power.

Flying, lifelink