msem-instigator

Chosen one ({W}{U}{B}{R}{G}: Transform this permanent.)
Whenever Fervent Ensign attacks, add {R} at the beginning of your next main phase.

Flying
You may exert Fervent Igmel as it attacks. When you do, add {R}{R}{R}{R}. Until end of turn, you don't lose this mana as steps and phases end. (An exerted creature won't untap during your next untap step.)

Attacking creatures you control get +1/+0.

Target creature gets +1/+0 and gains first strike and haste until end of turn.

{2}{R}{R}, Exile an instant or sorcery card from your graveyard: Fervid Dragonheart gets +1/+2, gains flying, and becomes a Dragon until end of turn.

Whenever a creature you control dies, put a rot counter on Fester Swarm and you gain 1 life.
{B}{G}, Remove two or more rot counters from Fester Swarm: Create a 1/1 green Insect creature token, then put a +1/+1 counter on it for each rot counter removed this way.

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

When Festering Shipwreck enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
At the beginning of each player's upkeep, that player sacrifices a nonland permanent.

At the beginning of your upkeep, mill a card.
{1}, Exile three cards from your graveyard: Put a -1/-1 counter on target creature.

When Festering Waif enters, each opponent mills two cards.
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.)

When Festival Celebrants enters, put a +1/+1 counter on each creature you control.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
{T}: Add {C}. If you're in a renaissance, add one mana of any color instead.
{3}, {T}: Scry 1.

Inspired — Whenever Festival Decorator becomes untapped, draw a card.

When Festival Rioters enters, create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”
{1}{R}: Festival Rioters gets +2/+0 until end of turn.

Choose one —
• Festival Sabotage deals 2 damage to any target.
• Audition for red. (Create a 1/1 Construct Actor creature token, a Warrior Role giving 3/2 and trample, or a Wizard Role giving 2/2 and prowess. Roles replace older ones.)

Harmony — Create a 1/1 white Bird creature token with flying.
{4}: Harmonize. (Trigger up to one harmony of one permanent you control.)

Destroy target enchantment and all other enchantments with the same name as that enchantment.
Draw a card.

Destroy target artifact and all other artifacts with the same name as that artifact.
Draw a card.

Target creature and all other creatures with the same name as that creature get +2/+2 until end of turn.
Draw a card.

Return target nonland permanent and all other permanents with the same name as that permanent to their owners' hands.
Draw a card.

Enchant creature you control
When Festive Euphoria enters, you gain life and draw cards equal to enchanted creature's power.
Enchanted creature can't be blocked by creatures with power 2 or less.

Choose one —
• Target attacking creature gets +2/+2 until end of turn.
• Destroy target artifact.

Festive Servitor gets +1/+1 for each color among spells you've cast this turn.
{2}: Add one mana of any color.

When Fetching Gancanagh dies, draw a card. At the beginning of the next end step, up to one target creature you control becomes a copy of Fetching Gancanagh.

{B}: Fetid Nibbler gains deathtouch until end of turn.