msem-instigator

Harmony — Creatures you control get +1/+0 and gain vigilance until end of turn.
When Plume de Val Singer enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Whenever a player gains life, that player loses 2 life.

{1}{U}: Target creature can't be blocked this turn.

At the beginning of each upkeep, if it's an extra turn, end the turn.
If a player would search a library, that player searches the top four cards of that library instead.

({T}: Add {R} or {W}.)
As Prayer Hall enters, you may pay {1}. If you don't, Prayer Hall enters tapped.

Harmony — Exile another target creature until Pretentious Performer leaves the battlefield.
When Pretentious Performer enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Vigilance, trample
Prized Marshcroaker can block an additional creature each combat.

Enchant creature
Enchanted creature can't attack or block.
Enchanted creature has “{7}: Destroy Proselytize.”

Harmony — Pyrodancer deals 1 damage to each opponent.
When Pyrodancer enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Choose one —
• Radiant Outburst deals 3 damage to target creature.
• Harmonize twice. (To harmonize, trigger up to one harmony of a permanent you control.)

As long as it's your turn, Rallying Rector has first strike.
Whenever Rallying Rector attacks, you may discard a card. If you do, search your library for a card named Rallying Rector, reveal it, put it into your hand, then shuffle.

Enchant opponent
When Ranidaphobia enters, create a 1/1 blue Frog creature token.
Creatures enchanted player controls can't block Frogs.

Counter target spell unless its controller pays {1}. If they do, draw a card.

Tithe (As you cast this spell, you may tap three artifacts and/or creatures you control.)
Return target creature or planeswalker card from your graveyard to your hand. If this spell's tithe was paid, return that card to the battlefield instead.

Choose target player. Until end of turn, if a spell or ability that player controls would cause them to draw a card, each of their opponents draws a card instead.

Harmony — Destroy target artifact or enchantment.
When Rejoicing Aristocrats enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Remarkable Hunter must be blocked if able.

Lifelink
Whenever Repent, Daughter of Fallacy blocks or becomes blocked, it deals 3 damage to any target.

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
When Returned Bokor dies, return it to its owner's hand.

({T}: Add {U} or {R}.)
As Ritzy Parlor enters, you may pay {1}. If you don't, Ritzy Parlor enters tapped.

Flying

Choose one or both —
• Riverboat Assault deals 3 damage to target creature.
• Target creature gets +3/+3 until end of turn.

Harmony — Untap target permanent.
Whenever you cast an instant or sorcery spell, harmonize. (Trigger up to one harmony of one permanent you control.)

Artifacts and lands enter tapped.