msem-instigator

Target opponent takes an extra turn after this one. Until your next turn, you control that player during extra turns.
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)

First strike
{1}{R}: Hatsuo, Honored General and other Warrior creatures you control get +1/+0 until end of turn.

Deathtouch, lifelink
Whenever Batwing Initiate deals combat damage to a player, put a +1/+1 counter on it.
Pay 4 life: Batwing Initiate gains flying until end of turn.

Target creature phases out. Its controller sacrifices a creature. (Treat the phased out creature and anything attached to it as though they don't exist until its controller's next turn.)

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Qilan Seer envisions a creature card, it gets +4/+0 until end of turn.

All creatures get -X/-X until end of turn. X can't be 0.
Whenever a creature dies this turn, create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

[+2]: Add {R}{R}. Until end of turn, red mana doesn't empty as steps and phases end, and creatures you control gain “{R}: This creature gets +1/+0 until end of turn.”
[–3]: You may cast a monocolored red spell with mana value 6 or less from your hand without paying its mana cost.
[–6]: You may pay any amount of {R}. When you do, Amelie Mayn deals that much damage to each of up to that many different targets.

Post a bounty on target creature you don't control, then each opponent sacrifices a creature. (Put a bounty counter on that creature. It has “When this creature dies, each opponent draws a card” as long as it has a bounty counter on it.)

Enchant creature with mana value 4 or less
When Cyclic Dream enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Deception {2}{U}{U} ({2}{U}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Raloran Insurgent deals combat damage to a player, abound. (You may cast a spell that costs less than this from your hand without paying its mana cost.)

When Seeker of Communions enters, choose target player. If that player is poisoned, draw a card. Otherwise, that player gets a poison counter.

As long as you control five or more creatures, if you would create a token, you may instead create Hu Li, a legendary 4/4 white Fox Spirit creature token with flying and lifelink.

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

{1}, Sacrifice Brackwater Scuttler: Draw a card.

Flying

Until end of turn, target creature gains deathtouch and “When this creature dies, return it to the battlefield tapped under its owner's control.”

Create two 1/1 colorless Servo artifact creature tokens.
Leitmotif (If you cast this spell from your hand, exile it as it resolves. When you next cast a spell that shares a color with this card, you may cast this from exile without paying its mana cost.)

When Long Lost Cause enters, each opponent exiles a card from their hand or a creature they control.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Over the Moon deals 4 damage to up to one target creature or planeswalker.
II, III — Until end of turn, spells you cast with mana value 4 or greater cost {1} less to cast and can't be countered.
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Trample
Resolute — {G}: Prowling Agamid gets +3/+3 until end of turn. Activate only once each turn and only if Prowling Agamid's power is greater than its base power.

{T}, Discard a card: Draw a card.
Unveil {2}{U}{R} ({2}{U}{R}: Transform this. Unveil only as a sorcery.)

Whenever you cast an enchantment, instant, or sorcery spell, create a 1/1 blue Jellyfish enchantment creature token with slipstream. (It can't be blocked as long as only creatures with slipstream are attacking.)

Enchant creature
Enchanted creature can't attack or block.
{2}{U}: Return Whiplash and enchanted creature to their owners' hands.

Return target creature or land card from your graveyard to your hand.