msem-instigator

Flying
Whenever Pledged Griffin attacks, another target attacking creature gains flying until end of turn.

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)
Trample

(Add a quest counter as this enters. Sacrifice after 3.)
Whenever an opponent loses 3 or more life, add a quest counter.
Destroy up to one target creature with power or toughness 2 or less.
Create Sir Jasper Reborn, a legendary 3/1 black Zombie Mouse Knight creature token with menace.
Search your library for a card, reveal it, put it into your hand, then shuffle. If you revealed a card named Karoa's Downfall this way, you may cast it without paying its mana cost.

Equipped creature gets +2/+1 and has flying.
Equip {3}

Target creature gets -3/-3 until end of turn. You gain 3 life. (Then exile this card. You may cast the creature later from exile.)

Whenever Poignant Hydra deals combat damage to a player, put a +1/+1 counter on it.
Creature spells you cast with power less than Poignant Hydra's power cost {1} less to cast.

This spell costs {2} less to cast if you control a creature with power 4 or greater.
Target creature gets +2/+0 and gains first strike and trample until end of turn.

Put two +1/+1 counters on target creature you control. When you do, it deals damage equal to its power to up to one target creature with flying.

You may cast cast up to two target instant and/or sorcery cards with total mana value 6 or less from your graveyard without paying their mana costs. If a spell cast this way would be put into your graveyard, exile it instead.
Exile Pointer Churn.

Whenever Poised Koi attacks or blocks, look at the top two cards of your library, put any of them into your graveyard, then the rest back on top in any order.

Target creature gains deathtouch and indestructible until end of turn.

Poisonblade Elite enters with three -1/-1 counters on it.
Whenever Poisonblade Elite becomes blocked, you may move a -1/-1 from it onto target creature blocking it.

Deathtouch
Poisoned Aleud must be blocked if able.

When Poisoned Shiv enters, destroy target creature or planeswalker.
Equipped creature gets +2/+0 and has deathtouch.
Equip {2}

Search your library for a land card and put that card onto the battlefield tapped with a venom counter on it. It gains “Whenever this land is tapped for mana, you lose 1 life.” Then shuffle.

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When Poisonheart Undead enters, you draw a card and you lose 1 life.

Put a -1/-1 counter on target creature. Target creature you control fights that creature.

Flash
Excess damage Polarity Sage would deal to an attacking creature is dealt to that creature's controller instead.

When Polgek Artisan enters, create an X/X colorless Juggernaut artifact creature token, where X is the number of artifacts and enchantments you control.

When Polgek Restorationist enters, you may return target artifact, enchantment, or planeswalker card from your graveyard to your hand.

This spell can't be countered.
Polis's Demise deals 5 damage to each creature. Destroy all artifacts.

Whenever a land enters under an opponent's control, that player loses 2 life and you gain 2 life.

When Polluted Servant enters, target opponent loses 1 life and you gain 1 life.
{2}{U}: Exile Polluted Servant, then return it to the battlefield tapped under your control.

When Polytheism enters, return up to four target permanent cards not named Polytheism from your graveyard to the battlefield. They become 4/4 God creatures in addition to their other types.
Gods you control have indestructible.

Inspired — Whenever Pon's Apprentice becomes untapped, target creature you control has base power and toughness 5/5 until end of turn.