Oaken Siren

Artifact Creature — Siren Pirate (1/2)

Flying, vigilance
: Add . Spend this mana only to cast an artifact spell or activate an ability of an artifact source.

Oculus

Creature — Phyrexian Homunculus (1/1)

When Oculus dies, you may draw a card.

Omenspeaker

Creature — Human Wizard (1/3)

When Omenspeaker enters the battlefield, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

Order of the Mirror // Order of the Alabaster Host

Creature — Human Knight // Creature — Phyrexian Knight (2/1)

: Transform Order of the Mirror. Activate only as a sorcery. ( can be paid with either or 2 life.)

Order of the Alabaster Host

Whenever Order of the Alabaster Host becomes blocked by a creature, that creature gets -1/-1 until end of turn.

Overtaker

Creature — Merfolk Spellshaper (1/1)

, , Discard a card: Untap target creature and gain control of it until end of turn. That creature gains haste until end of turn.

Owl Familiar

Creature — Bird (1/1)

Flying
When Owl Familiar enters the battlefield, draw a card, then discard a card.

Palace Familiar

Creature — Bird (1/1)

Flying
When Palace Familiar dies, draw a card.

Parcel Myr

Artifact Creature — Clue Myr (2/1)

, Sacrifice Parcel Myr: Draw a card.

Passwall Adept

Creature — Human Wizard (1/3)

: Target creature can't be blocked this turn.

Patchwork Crawler

Creature — Zombie Horror (1/2)

: Exile target creature card from your graveyard and put a +1/+1 counter on Patchwork Crawler.
Patchwork Crawler has all activated abilities of all creature cards exiled with it.

Phantasmal Image

Creature — Illusion (0/0)

You may have Phantasmal Image enter the battlefield as a copy of any creature on the battlefield, except it's an Illusion in addition to its other types and it has "When this creature becomes the target of a spell or ability, sacrifice it."

Phantasmal Mount

Creature — Illusion Horse (1/1)

Flying
: Target creature you control with toughness 2 or less gets +1/+1 and gains flying until end of turn. When Phantasmal Mount leaves the battlefield this turn, sacrifice that creature. When the creature leaves the battlefield this turn, sacrifice Phantasmal Mount.

Piper Wright, Publick Reporter

Legendary Creature — Human Detective (1/2)

Whenever Piper Wright deals combat damage to a player, investigate that many times. (To investigate, create a Clue token. It's an artifact with ", Sacrifice this artifact: Draw a card.")
Whenever you sacrifice a Clue, put a +1/+1 counter on target creature you control.

Plated Seastrider

Creature — Beast (1/4)

Plaxmanta

Creature — Beast (2/2)

Flash
When Plaxmanta enters the battlefield, creatures you control gain shroud until end of turn. (They can't be the targets of spells or abilities.)
When Plaxmanta enters the battlefield, sacrifice it unless was spent to cast it.

Pollywog Symbiote

Creature — Frog (1/3)

Each creature spell you cast costs less to cast if it has mutate.
Whenever you cast a creature spell, if it has mutate, draw a card, then discard a card.

Prize Wall

Creature — Wall (0/4)

Defender
, : You get .
, : You may put a sticker on a nonland permanent you own. Activate only as a sorcery.

Protean Thaumaturge

Creature — Human Wizard (1/1)

Constellation — Whenever an enchantment enters the battlefield under your control, you may have Protean Thaumaturge become a copy of another target creature, except it has this ability.

Purple-Crystal Crab

Creature — Crab (1/1)

When Purple-Crystal Crab dies, draw a card.

Qarsi Deceiver

Creature — Naga Wizard (0/4)

: Add . Spend this mana only to cast a face-down creature spell, pay a mana cost to turn a manifested creature face up, or pay a morph cost. (A megamorph cost is a morph cost.)