msem-instigator

Siphon (Each -1/-1 counter you put on your creatures up to their remaining toughness while casting this pays for {1}.)
Choose up to X, where X is the amount of mana spent to cast this spell —
• Target creature gets -3/-3 until end of turn.
• Surveil 2.
• Create a 1/1 black Bat creature token with flying and “This creature can't block.”

Whenever you lose 2 or more life during your turn, put two blood counters on Hemomancy.
{1}{B}, Remove X blood counters from Hemomancy: Return target creature card with mana value X from your graveyard to the battlefield.

Lifelink

Pressure {2}{B} (You may cast this spell for its pressure cost if there are seven or more cards in your graveyard.)
Menace (This creature can't be blocked except by two or more creatures.)

When Herald of Darkness enters, destroy up to one target creature with mana value 3 or less.

(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.

Whenever another Knight or Soldier you control enters, target player loses 1 life.

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.)