msem-instigator

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

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

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

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.

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

Enchant creature
Enchanted creature gets -1/-3.

Whenever you cast an instant or sorcery spell, look at the bottom card of your library. You may manifest it. If you don't, put it into your hand. (To manifest a card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

At the beginning of each player's upkeep, sacrifice Hayuan, the Misjudged if that player controls a creature with power 2 or less.
When Hayuan dies, create X Idol tokens, where X is the number of creatures you control. (They're artifacts with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Haste (This creature can attack and {T} as soon as it comes under your control.)
Mirage {R} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

({T}: Add {U} or {B}.)
Hazy Moorland enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

({T}: Add {G} or {W}.)
Heart of the Glade enters tapped unless you control a basic Forest or a basic Plains.

Menace
Sacrifice a Goblin: Heartless Warleader gets +2/+2 until end of turn.

Kicker {2}{B} (You may pay an additional {2}{B} as you cast this spell.)
Flying
When Heartstabber Mosquito enters, if it was kicked, destroy target creature.

Whenever a creature blocks, Heat of Battle deals 1 damage to that creature's controller.

Until end of turn, gain control of target creature and it gains haste and shimmer. Untap it. (Whenever it attacks this turn, create a tapped and attacking token that's a copy of it. Exile that token at the beginning of the end step.)

Heated Dispute deals 3 damage to any target.
Ferocious — This spell costs {2} less to cast if you control a creature with power 4 or greater.

Shuffle your library, then reveal cards from the top of your library until you reveal a creature card. Put that card onto the battlefield and the rest on the bottom of your library in a random order. Heathen Rise deals damage to you equal to the number of cards revealed this way.
Ferocious — That creature gains haste if it has power 4 or greater.

Vigilance
{W}: Heaven's Champion gains first strike until end of turn.

Flying, lifelink

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever a creature you control with flying attacks, it gets +1/+1 until end of turn.

{T}: Add {C}.
When Heavenly Temple enters, target creature gains flying until end of turn.
{2}: Return Heavenly Temple from the battlefield to its owner's hand.

Flying (This creature can't be blocked except by creatures with flying or reach.)
Heavensent Emissary enters with a +1/+1 counter on it for each other creature with flying you control.

Trial 3 (As you cast this spell, an opponent of your choice may pay 3 life. If they don't, they fail the trial.)
When Heedless Adversary enters, you may have it deal 3 damage to target creature if that creature's controller failed the trial.