msem-instigator

Flying
Assault {2}{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 Harbinger of Locusts assaults, you may search your library for an Insect card, reveal it, put it into your hand, then shuffle.

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.

When Into the Lion's Den enters, target opponent reveals their hand. You choose a nonland card from it and exile that card until Into the Lion's Den leaves the battlefield.

Destroy target creature. Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Whenever Merchant of Flesh or another creature you control dies, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
{B}, Sacrifice two Treasures: Each opponent sacrifices a creature.

Nameless Throng can't block.
{1}{B}, Exile an artifact or enchantment card from your graveyard: Return Nameless Throng from your graveyard to the battlefield.

Enchant creature
When Paid in Blood enters, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
Enchanted creature gets +1/+1 and has lifelink.

Return target artifact or creature card from your graveyard to your hand.
Draw a card.

Deathtouch

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards.

When Scorpid Sniper enters, you may have target creature get -1/-1 until end of turn.

At the beginning of your end step, for each opponent, destroy up to one target creature that player controls with power less than or equal to the amount of life that player lost this turn.
{3}{R}: Selezzar, Tyrant of Endak deals 2 damage to each opponent.

Target opponent separates all creatures into two piles. You choose one of those piles. For each creature in the chosen pile, its controller sacrifices it.

Target player discards two cards.

Menace (This creature can't be blocked except by two or more creatures.)
Sacrifice another creature: Stingbrood Warlord gains deathtouch until end of turn.

Enchant creature
Enchanted creature gets -3/-0 and can't block.

I, II — Mill two cards. You gain 2 life. (Put the top two cards of your library into your graveyard.)
Discovery — During each of your turns, you may cast a permanent spell from your graveyard.

I, II — Each opponent loses 2 life and you gain 2 life.
Discovery — At the beginning of your end step, you draw a card and you lose 2 life.

At the beginning of each opponent's upkeep, that player may discard their hand. If the player does, sacrifice Under the Gun. Otherwise, put a bullet counter on Under the Gun, then that player loses life equal to the number of bullet counters on it.

Flying
Assault {2}{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 Wretched Lammasu assaults, each opponent discards a card.

Create two 1/1 red Elemental creature tokens.

Create two 1/1 red Elemental creature tokens. When you do, target creature you control gets +X/+X and gains trample until end of turn, where X is the number of Elementals you control.

Blazing Offerings deals 4 damage to target creature or planeswalker.