msem-instigator

Flying
Whenever a creature you control dies, each opponent loses life equal to its power.

When Monstrous Hunter enters, destroy up to one target creature.
At the beginning of each end step, if a creature died this turn, you draw a card and you lose 1 life.

Equipped creature gets +1/+1 and has “{5}, {T}: This creature fights another target creature.”
Equip {5} ({5}: Attach to target creature you control. Equip only as a sorcery.)

Whenever another non-Zombie creature you control dies, create a tapped 2/2 black Zombie creature token.
{B}, Sacrifice a creature: Target creature gains deathtouch until end of turn.

{T}, Remove a +1/+1 counter from a creature you control: You draw a card and you lose 1 life.

Equipped creature gets +4/+2 and has first strike, vigilance, and trample.
Equip {3}

Flying, first strike
Whenever Terror of Sunset Cliffs attacks, each player discards their hand and draws seven cards.
Whenever an opponent discards a card, Terror of Sunset Cliffs deals 1 damage to that player.

Menace
Other artifact creatures you control have menace.
{2}{B}{R}: Salvage an artifact or creature card. (Exile one from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)

Search your library for a creature card, reveal it, then shuffle and put that card second from the top.

Whenever another creature with power 4 or greater you control attacks, Ruthless Brawler deals 1 damage to defending player.

Flash
Whenever a permanent with an Adventure you control enters, put a +1/+1 counter on Wandering Dingo.

Flying
Whenever another creature you control enters, you may have Waxing Celestial get +1/+1 until end of turn.

{3}, {T}: Each opponent loses 2 life. This ability costs {3} less to activate if you've sacrificed a permanent this turn.

Search target opponent's library for a nonland card. You may cast that card without paying its mana cost. Then that player shuffles.
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)

Exile target creature. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Wither (This deals damage to creatures in the form of -1/-1 counters.)
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Up to two target lands you control become 1/1 black Bear creatures with deathtouch. They're still lands. (Then exile this card. You may cast the creature later from exile.)

{6}{U}: Brume Trench-Thrasher can't be blocked this turn. This ability costs {1} less to activate for each instant and sorcery card you own in exile and in your graveyard.

Flying
Whenever Aether Crosser attacks, you may aetherize another target tapped creature you control. (To aetherize, create a token that's a copy of it, then exile that token.)
Crew 1

Descended Marsh enters tapped.
{T}: Add {B} or {G}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Concord — Once each turn, when an opponent casts a spell or activates an ability that targets a Merfolk or enchantment you control, you may counter that spell or ability if there are four or more card types among permanents you control.

Escalate {G}{G} (Pay this cost for each mode chosen beyond the first.)
Choose one or more. You may choose the same mode more than once.
• Create a 3/3 green Beast creature token.
• Search your library for a land card, put it onto the battlefield tapped, then shuffle.

Indestructible
Spells you cast from your graveyard cost {6} less to cast.
Whenever you attack, you may cast any number of target cards from your graveyard this turn. If a spell or permanent that was cast this way would be put into a graveyard, exile it instead.

{3}: Sellsword Contraption becomes the creature type of your choice until end of turn.

When this creature enters, create a 1/1 white Bird creature token with flying.
{3}{W}, Exile this card from your graveyard: Create a 1/1 white Bird creature token with flying. Activate only as a sorcery.