msem-instigator

As Precursor Gate leaves the battlefield, you may exile it. When you do, destroy target nonland permanent.
{5}, {T}, Sacrifice Precursor Gate: Draw a card.

Whenever Precursor Omniprocessor attacks, you may sacrifice an artifact or creature. If you do, put a +1/+1 counter on Precursor Omniprocessor and it gains menace until end of turn.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

Equipped creature gets +1/+1 and has menace.
Equip {R}

Predatory Abomination has deathtouch and lifelink as long as you control another Horror.

Search your library for a creature card, reveal it, put it into your hand, then shuffle. Then if you control a creature with power 4 or greater, you may pay {4}. If you do, you may put a creature card from your hand onto the battlefield.

Vigilance
Whenever another creature you control enters, scry 1.
{T}: Reveal the top card of your library. If it's a creature card, put it into your hand. Otherwise, you may put it into your graveyard.

Reach
When Primordial Artisan enters or attacks, look at the top card of your library. If it's a permanent card with mana value less than or equal to your devotion to green, you may put it onto the battlefield. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)

Pristine Delta enters tapped.
{T}: Add {W} or {U}.
{2}{W}{U}, {T}, Sacrifice Pristine Delta: Draw a card.

Flying
Whenever you scry, create a 1/1 blue Chimera creature token with flying. This ability triggers only once each turn.

Scry 1. Draw a card. Scry 1.

Enchant creature
When Prophet's Paranoia enters, tap enchanted creature, then scry 2.
Enchanted creature loses all abilities and doesn't untap during its controller's untap step.

When Propulsion Pack enters, create a 1/1 colorless Servo artifact creature token and attach Propulsion Pack to it.
Equipped creature gets +1/+1 and has flying.
Equip {3}{U}

As Protean Jar enters, choose a creature type.
Each creature you control of the chosen type enters with an additional +1/+1 counter on it.
{2}: If Protean Jar isn't a creature, it becomes a copy of target creature you control of the chosen type, except it has Protean Jar's other abilities. Activate only as a sorcery.

Counter target spell unless its controller pays {2}.
Put a +1/+1 counter on a creature you control.

Flash
When Purehorn Rescuer enters, return target permanent card with mana value X or less from your graveyard to the battlefield, where X is your devotion to white. (Each {W} in the mana costs of permanents you control counts toward your devotion to white.)

Enchant creature you control
When Purphoros's Benefaction enters, scry 2.
Enchanted creature gets +1/+1 and has haste.

Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Purphoros's Gemback deals 1 damage to target player or planeswalker.
[Lore III] Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Indestructible
As long as your devotion to red is less than five, Purphoros isn't a creature.
Whenever you attack, Purphoros deals 1 damage to any target.
{3}{R}: Discard up to two cards, then draw that many cards.

Flying
When Pyromanticore enters, it deals X damage to target creature or planeswalker an opponent controls, where X is your devotion to red. Excess damage is dealt to that permanent's controller instead. (Each {R} in the mana costs of permanents you control counts toward your devotion to red.)

{T}: Add {C}.
{1}, {T}: Add one mana of any color. This ability costs {1} less to activate if there are three or more colors among cards in your graveyard.

Rhapsody {4}{R}{R} (Pay {4}{R}{R} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
When Reckless Guardian dies, create X 1/1 colorless Servo artifact creature tokens, where X is Reckless Guardian's power.

Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

When Reconnaissance Expert enters, mill four cards.
When Reconnaissance Expert dies, return target noncreature permanent card from your graveyard to your hand.

Counter target spell.
{1}{U}, Exile Refute from your graveyard: Draw a card.

Flying, lifelink, haste
{W}{U}{B}{R}{G}, Exile Remi Amber, Slyten Specialist: Return Remi Amber to the battlefield transformed at the beginning of your next main phase.