msem-instigator

Lethal damage dealt to creatures is determined by their power rather than their toughness.

If a source would deal damage to a creature in Cascading Zhenzu's pack, prevent 1 of that damage. (Two or more creatures you control with equal power are in a pack.)
{U}: You may switch Cascading Zhenzu's power and toughness until end of turn.

Menace

Whenever Abyssal Stalker attacks, defending player discards a card at random.
When Abyssal Stalker dies, you may choose a creature. If you do, exile Abyssal Stalker. When the chosen creature leaves the battlefield, return Abyssal Stalker from exile to the battlefield tapped.

Menagerie — When Grotto Guardian enters, if there are five or more creature types among creatures you control, target creature you don't control gets -2/-2 until end of turn.

Poisonous 5 (Whenever this creature deals combat damage to a player, that player gets five poison counters.)
At the beginning of your upkeep, if an opponent is poisoned, you may destroy target Human.

When Data Smuggler enters, if an opponent is cursed, exile the top card of your library. You may play that card until the end of your next turn.

Trample
Whenever Fellor Razer deals combat damage to a player, that player sacrifices a land.

Prismatic — Whenever you cast a multicolored spell, you may discard a card. If you do, draw a card.

Maniac Macaque attacks each combat if able.
Whenever Maniac Macaque becomes blocked by a creature, Maniac Macaque deals 1 damage to that creature.

Colossal 3—{6}{R} (You may cast this for its colossal cost to have it enter with three +1/+1 counters; or pay {6}{R} as a sorcery: Put three +1/+1 counters on it if it has none.)

{3}{G}: Scaled Devestator gets +1/+1 and gains trample until end of turn.

Hexproof
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.)

First strike
Whenever Deprived Div deals combat damage to an opponent, end the turn. (Creatures without first strike won't deal damage this turn.)

When Gleamhorn Gargantuan enters, put a +1/+1 counter on up to one other target creature.
Cycling {2} ({2}, Discard this card: Draw a card.)

Concord — Lurking Lahasia has first strike and lifelink as long as there are four or more card types among permanents you control.

When Ethereal Spellmaster enters, if it was cast, you may search your library for an instant or sorcery card with mana value 3 or less and cast it without paying its mana cost. If you do, shuffle your library. (If it has X in its mana cost, X is 0.)

Creatures with power less than Pharaoh Guardian's power can't block it.

{U}: Pilgrim's Muse can't be blocked this turn.
{1}{U}: Return Pilgrim's Muse to its owner's hand.
{2}{U}: Scry 2.
{3}{U}: Draw a card.

Whenever Arisen Rider attacks, creatures your opponents control get -1/-1 until end of turn.
If Arisen Rider or another creature or planeswalker would die, exile it instead.

When Bloodpact Tormentor enters, you may put a -1/-1 counter on target creature.
Bloodpact Tormentor can't be blocked by creatures with counters on them.

Disgraced 2 (This enters with two -1/-1 counters. Whenever it deals combat damage to a player, remove all -1/-1 counters from it.)
When Branded Contractor dies, you may put its counters on target creature.

Menace
When Darna's Atrocity enters, you may pay 2 life. If you do, you draw two cards and mill two cards.
{B}, Exile a card from your graveyard: Darna's Atrocity gets +1/+1 until end of turn.

Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{3}{B}{B}: Choose any number of other nontoken creatures you control. Whenever one of those creatures dies this turn, create a token that's a copy of that creature, except it has no mana cost.