msem-instigator

Whenever another creature you control enters, Loisch deals 1 damage to any target.
{4}{R}{G}: Loisch gets +X/+X and gains trample until end of turn, where X is the number of creatures you control.

Menace
When Lone Zombie and at least two other creatures attack, transform Lone Zombie.

When Loyal Retriever dies, search your library for an Aura or Equipment card, reveal it, put it into your hand, then shuffle.
Foreshadow {5}{W} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

When Lupine Prowler enters, you may sacrifice another creature. If you do, draw a card and you gain 2 life.
Whenever another creature you control dies, put a +1/+1 counter on Lupine Prowler.

Choose target creature you control. You may transform it if it's a Werewolf. Then it deals damage equal to its power to target creature you don't control. (The creature you control bites even if you don't transform it.)

Other Pirates and Rogues you control get +1/+0.
Whenever you attack with three or more Pirates and/or Rogues, tap target creature.

Spells you cast from anywhere other than your hand cost {1} less to cast.
At the beginning of combat on your turn, another target Pirate or Rogue you control gets +X/+0 and gains haste until end of turn, where X is the number of noncreature spells you've cast this turn. That creature can't be blocked this turn.

Macabre Pools enters tapped. When it enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
{T}: Add {U} or {B}.

You have no maximum hand size.
Whenever Makodonis's Wolfbro attacks, if its power is greater than its base power, draw cards equal to the difference.

If a creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
[+1]: Target player draws two cards, then discards a card. Put a +1/+1 counter on up to one target creature you control.
[–3]: Create a token that's a copy of target creature you control.
[–8]: Return any number of target nonland permanents to their owner's hand.

This spell costs {2} less to cast for each Curse you control.
Flying, vigilance, haste

All creatures get -2/-2 until end of turn. If a creature an opponent controls would die this turn, exile it instead.

Lifelink
When this creature enters, put a -1/-1 counter on a creature you control.

When March of the Unhallowed enters, mill three cards, then return a creature card with mana value 3 or less from your graveyard to the battlefield.
Whenever you attack with three or more creatures, each opponent loses 1 and you gain 1 life.

{T}: Draw a card, then discard a card. If you discarded an instant, sorcery, Pirate, or Rogue card this way, create a 1/1 blue Tentacle creature token with “This creature can't block.”

When this creature enters, put a -1/-1 counter on a creature you control.
Whenever you put one or more -1/-1 counters on one or more creatures, surveil 2.

This spell costs {2} less to cast if you've foretold a card from your hand this turn.
Whenever this creature enters or attacks, draw a card, then exile a card from your hand face down. It becomes foretold. (You can only cast it later if it has foretell.)

{1}{W}: Markov Fencer gains first strike until end of turn. You gain 1 life.

Until end of turn, target creature gets +3/+0 and gains “When this creature dies, return it to the battlefield tapped under its owner's control.”
Foretell {B} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Flying, double strike
Whenever Marzela Falkenrath deals combat damage to a player, create a 1/1 black and red Vampire creature token with menace.
{2}{B}: Vampires you control gain lifelink until end of turn.

Your opponents can't gain life.
If a source you control would deal damage to an opponent, it deals double that damage instead.
At the beginning of your end step, if Mayhem Tandem didn't attack this turn, transform it.

Return up to one target nonland permanent to its owner's hand. If you control a creature with flying, surveil 2.

Flash
Flying
When Mellan enters, exile up to one other target nonland permanent with mana value equal to or less than the number of creatures you control with flying until Mellan leaves the battlefield.

Vigilance
{2}, {T}: Target player mills two cards.

Siphon (Each -1/-1 counter you put on your creatures up to their remaining toughness while casting this pays for {1}.)
You gain X life and draw X cards, where X is the number of creatures that died this turn.