msem-instigator

(Transform this if it's not attached to a creature. Pay {B} as a sorcery to unattach it.)
Enchant creature you control
Herald of Death's rider gets +1/+1.
Sacrifice a creature: Herald of Death's rider gets +2/+2 until end of turn.

Flying
Herald of Oblivion enters with X -1/-1 counters on it, where X is your life total.

Flying
Whenever Herald of Shadow attacks, another target creature can't be blocked this turn.
Whenever a creature you control deals combat damage to an opponent, exile the top card of that player's library. 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 it.

You may cast Heralds of Shikai from your graveyard as long as a creature an opponent controls died this turn.

When Heretic's Vow enters, create two 1/1 white Cleric creature tokens with lifelink.
Once each turn, when you gain life, you may put a +1/+1 counter on target creature you control.

Deathtouch
Whenever a storied permanent you control enters, remove up to two counters from target creature or planeswalker an opponent controls. (Enchantments and legendary permanents are storied.)

Destroy target creature or planeswalker.

When Hex Maniac enters, return target non-Human creature card from your graveyard to your hand.

Whenever you cast an instant or sorcery spell, each opponent loses 1 life and you gain 1 life.

When Hextwister Hare enters, if you control another Shaman or there's a Shaman card in your graveyard, each opponent discards a card.

Whenever a player casts a spell, that player reveals cards from the top of their library until they reveal two land cards, then puts all cards revealed this way into their graveyard.

At the beginning of your upkeep, if you control a legendary creature, you draw a card and you lose 1 life.

Destroy target tapped creature.
Menagerie — If there are five or more creature types among creatures you control, that creature's controller discards a card.

Assault {B} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
When Hilaback Outriders assaults, it gains menace until end of turn.

Destroy all creatures and planeswalkers with mana value X or less.

Choose three. You may choose the same mode more than once.
• You draw a card and you lose 1 life.
• Target opponent discards a card and loses 1 life.

Enchant creature
Enchanted creature gets +2/+0.
{2}{B}, Exile Hold Me Down from your graveyard: Return target creature card from your graveyard to your hand.

When Hollowflesh Ghoul dies, create a 1/1 black Skeleton creature token.

Flying, deathtouch
Revive {3}{B} ({3}{B}, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost. Activate this ability only any time you could cast a sorcery.)

When Honey Pot enters, create two 1/1 black Demon enchantment creature tokens with breach and “This creature can't block.” (Whenever it deals combat damage to a player, you may have it become an Aura Curse until your next turn. Attach it to that player.)
Whenever a Curse you control becomes attached to an opponent, that player loses 1 life and you gain 1 life.

Menace
Whenever Hope Wrangler attacks, target attacking creature with lesser power gains menace until end of turn.

When you attain Hopeless Lanonshee, create two 1/1 black Construct artifact creature tokens.
Whenever a creature dies, each opponent loses 1 life and you gain 1 life.

Whenever Hopeless Romantic or another creature you control dies, each opponent loses 1 life.
Attain {3}{B} ({3}{B}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Trample
Whenever Horrific Progenitor deals damage to a player, for each damage dealt, that player loses 3 life unless they sacrifice a nonland permanent or discard a card.

Pressure {3}{B} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
Return target creature card from your graveyard to your hand. If this spell was cast for its pressure cost, put that card onto the battlefield instead.