msem-instigator

When Grim Festivities enters or at beginning of your upkeep, you may return a creature card from your graveyard to the battlefield under your control. If you do, each opponent may return a creature card from their graveyard to their hand.

Sacrifice another creature: Grindlesnap gets +3/+2 and gains trample until end of turn if that creature was a Crocodile. Otherwise, it gets +1/+1 until end of turn.
Whenever Grindlesnap is dealt combat damage, create a 3/2 green Crocodile creature token with trample.

Enchant opponent
When Grisly Hunger enters, enchanted player's life total becomes 10.
At the beginning of enchanted player's end step, they sacrifice a creature. If they do, they lose life equal to that creature's power.

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

Untap target creature. It gets +1/+3 until end of turn.

Tithe (As you cast this spell, you may tap three artifacts and/or creatures you control.)
Creatures you control gain indestructible until end of turn. If this spell's tithe was paid, put a +1/+1 counter on each creature you control.

Flying, haste
Whenever you attack with three or more creatures, harmonize three times. (To harmonize, trigger up to one harmony of a permanent you control.)
If you would harmonize, you may instead return Herald of Festivities from your graveyard to your hand.

Enchant opponent
Spells you cast that target enchanted player cost {2} less to cast.

Harmony — Target creature gains indestructible until end of turn.
When Improvising Automaton enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Escalate {R} (Pay this cost for each mode chosen beyond the first.)
Choose one or both —
• Untap all creatures you control.
• Take an extra turn after this one. Skip the untap step of that turn. Exile Inspire Actuality.

Harmony — Target creature gets +2/+2 until end of turn.
When Inspiring Band enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Attacking creatures get +2/+0 and gain trample until end of turn.

When Irrigation Trawler enters, reveal the top card of your library. If that card was a land card, put that card into your hand. Otherwise, create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

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.)
{T}: The next creature spell you cast this turn has enspirit. When that creature enters, it becomes an enchantment in addition to its other types.

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 Kantra of Avarice enters, target player draws two cards and loses 2 life.

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.)
Trample

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.)
Lifelink

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.)
At the beginning of each player's upkeep, they sacrifice a nonenchantment creature. Then if there are no nonenchantment creatures on the battlefield, sacrifice Kantra of Plagues.

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast enchantment spells.

({T}: Add {W} or {U}.)
As Lakeside Park enters, you may pay {1}. If you don't, Lakeside Park enters tapped.

At the beginning of your upkeep, target player draws a card and loses 1 life. Each other player creates a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

Each player may play an additional land on each of their turns.
Whenever a land enters, each player may draw a card.

Menace
Lonely Devil can't attack or block alone.

Exile the top three cards of your library. For each land card exiled this way, create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.” Until the end of your next turn, you may cast nonland cards exiled this way.

Put target nonland permanent on top of its owner's library.
Create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”