msem-instigator

Discard your hand. Creatures you control get +X/+0 and gain first strike until end of turn, where X is the number of cards discarded this way.

When Hate-Driven Arsonist enters, you may have it deal X damage to target creature or planeswalker, where X is the number of instant and sorcery cards in your graveyard.

Target player discards two cards and loses 2 life. Scry 2. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

When Hatewracked Explorer enters, you may sacrifice an artifact or creature. If you do, crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)
{4}{B}{R}, Sacrifice an artifact or creature: Destroy target creature if it was dealt damage this turn.

Each player discards their hand, then draws cards equal to the greatest number of cards discarded this way.

Reprise {3}{R} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)
Hatsuo's Maneuver deals 1 damage to any target. Create a number of 1/1 red Warrior creature tokens equal to the damage dealt by this spell.

First strike
{1}{R}: Hatsuo, Honored General and other Warrior creatures you control get +1/+0 until end of turn.

Haughty Chateau enters tapped unless you have two or more opponents.
{T}: Add {W} or {B}.

When Haughty Paladin enters, you may sacrifice another artifact or creature. If you do, tap all creatures your opponents control.

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

Defender
Civilized — As long as you control an artifact, a creature, and an enchantment, Hauling Hippopotamus can attack as though it didn't have defender.

{T}: Add {C}.
{T}, Pay 1 life: Add {B} or {G}.

Haunted Estate enters tapped unless another player controls a land that could produce {W} or {B}.
{T}: Add {W} or {B}.

{T}: Add {C}.
{T}, Reappropriate: Add {U} or {R}. (Exile exactly two cards from your hand and/or graveyard.)

When Haunted Heirloom dies, create a Treasure token.

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

Haunted Hovel enters tapped.
{T}: Add {W} or {B}.
When Haunted Hovel enters, you may put a loyalty counter on a planeswalker you control.

{T}, Pay 1 life: Add {W} or {U}.
{2}, {T}, Sacrifice Haunted Manor and another permanent: Draw a card. Activate only during your turn.

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.

Haunted Woodlock enters tapped unless you have two or more opponents.
{T}: Add {B} or {G}.

Flying
Whenever Haunter of the Deadlands attacks, Spirit creatures you control get +1/+1 until end of turn.

{W}, Sacrifice Haunting Bard: Destroy target artifact or enchantment.

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

Flying
Whenever Haunting Horseman deals combat damage to a player, that player discards a card.

Enchant creature
Enchanted creature gets -1/-3.