msem-instigator

Germinate three times. You lose 3 life. (To germinate, put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards. You gain 2 life.

Flying
First strike (This creature deals combat damage before creatures without first strike.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Haste (This creature can attack and {T} as soon as it comes under your control.)
{1}{U}: Balloon Dragoon gains flying until end of turn.

At the beginning of combat on your turn, if there are five or more creature types among creatures you control, creatures you control get +2/+0 and gain menace until end of turn.

Blazing Volley deals 1 damage to each creature your opponents control.

Whenever another creature you control enters, you may have it gain haste. If you do, return it to its owner's hand at the beginning of the next end step.

Menace
When Bogborn Exorcist enters, you may discard a card. When you do, exile target instant or sorcery card with mana value 3 or less from an opponent's graveyard. Copy that card. You may cast the copy without paying its mana cost.

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Harmony — Create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”
When Bouquet Singer enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Sacrifice another creature: Brash Hunter deals 1 damage to any target.
At the beginning of your end step, if three or more creatures died this turn, transform Brash Hunter.

Sacrifice another creature: Grisly Rougarou deals damage equal to the sacrificed creature's power to any target.

Tithe (As you cast this spell, you may tap three artifacts and/or creatures you control.)
Any opponent may have you draw three cards. If they don't, Burning Revelations deals 5 damage to them. Then if you cast this spell and its tithe was paid, copy it twice.

Tithe (When this creature enters, you may tap three other artifacts and/or creatures you control.)
When Cataclysmic Preacher's tithe is paid, return target instant or sorcery card from your graveyard to your hand.

Enchant opponent
The first time enchanted player chooses targets each turn, reselect each of those targets at random.

Tithe (As you cast this spell, you may tap three artifacts and/or creatures you control.)
Damning Flames deals 3 damage to any target. If this spell's tithe was paid, it deals 6 damage instead.

When Dazzling Festivities enters or at the beginning of your upkeep, you may have each player reveal the top card of their library. Starting with you, each player may cast a nonland card revealed this way without paying its mana cost.

Disrupting Storms deals 3 damage to target player. That player sacrifices a land.

Elegant Strike deals 2 damage to target tapped creature. Create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

Untap each creature you control. After this main phase, there is an additional combat phase followed by an additional main phase. At the beginning of your end step, sacrifice each creature you control that attacked this turn.

Harmony — Exciting Band deals 3 damage to any target.
When Exciting Band enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Tithe (As you cast this spell, you may tap three artifacts and/or creatures you control.)
Faradia's Outrage deals X damage to any target. If this spell's tithe was paid, it deals X damage divided as you choose among any number of targets instead.

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

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.