msem-instigator

{1}, Sacrifice Aberrant Apostle: Choose one. This ability costs {1} less to activate as long as Aberrant Apostle entered this turn.
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.

Abyss Howler must be blocked if able.
Whenever Abyss Howler becomes blocked, defending player loses 2 life and you gain 2 life.

This spell costs {2} less to cast if you've cast both an instant spell and a sorcery spell this turn.
Haste

Flying
Whenever you draw a card, put a +1/+1 counter on Acolyte of Life.
Remove two counters from Acolyte of Life: It phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)

Whenever you draw a card, put a +1/+1 counter on Acolyte of Water.
Surpass {5}{U} ({5}{U}: Transform this creature. This costs {1} less to activate for each counter on it. Activate only as a sorcery.)

Whenever you cast a noncreature spell, put a +1/+1 counter on Adrift Surveyor.
Surpass {5}{U} ({5}{U}: Transform this creature. This costs {1} less to activate for each counter on it. Activate only as a sorcery.)

Whenever you cast an Adventure spell, put a +1/+1 counter on Adventurer Extraordinaire.

When Aether Sculptor enters, create a tapped colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

Menace, trample, indestructible
Whenever Aghavaan Unleashed deals combat damage to a player, that player gets that many poison counters.
At the beginning of your end step, sacrifice another creature or transform Aghavaan Unleashed.

{T}: Add {C}.
At the beginning of each end step, if you control five or more Snake creatures, transform Aghavaan's Wound.

[+1]: Whenever a creature you control attacks this turn, Aleryn, Dungeon Disabler deals 1 damage to the defending player.
[–1]: Add X mana in any combination of {R} and/or {G}, where X is the number of creatures you control.
[–6]: You get an emblem with “Whenever a player casts a spell, this emblem deals 3 damage to any target.”

Whenever a land you control enters, create a 1/1 red Elemental creature token. Then if you control three or more Elementals, exile Aleryn, Trapseeker, then return him to the battlefield transformed under his owner's control.

Create two 2/1 black and red Cat Pirate creature tokens with menace. You lose 2 life.

Alluring Rider must be blocked if able.
Attain {4}{G} ({4}{G}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Trample
Whenever a Warrior you control dies, it deals 1 damage to any target.

As this permanent transforms into Ameret, Shining and Proud, counters on them become loyalty counters instead.
[+1]: Until end of turn, you may have Ameret become an X/X Angel creature with flying, indestructible, and haste, where X is the number of counters on them.
[–2]: Create three 1/1 red and white Cleric creature tokens with lifelink and haste.

Trample
When Ancient Pillan enters, it fights up to one target creature an opponent controls.

Sacrifice a creature. When you do, draw two cards. (Then exile this card. You may cast the creature later from exile.)

Protection from instants and from sorceries
At the beginning of your upkeep, sacrifice another creature. For each creature sacrificed this way, put a +1/+1 counter on Andazir, the Crownless.
At the beginning of your end step, if you control four or fewer creatures, transform Andazir.

Hexproof
You have hexproof.
If a source would deal damage to you, prevent 1 of that damage.
{1}, Sacrifice two permanents: Draw two cards. Activate only during your turn.

As Animus, Life's Entropy enters, choose a color.
You and Animus each have hexproof from the chosen color.
Attain {6} ({6}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Activated abilities of sources you don't control can't be activated unless they're mana abilities.

Whenever you cast a noncreature spell, put a +1/+1 counter on Anointed Truthseeker. Up to one target creature can't block Anointed Truthseeker this turn.

Draw three cards. You gain 3 life. Apex deals 3 damage to any target.

Sacrifice a creature. Draw cards equal to its power and gain life equal to its toughness. (Then exile this card. You may cast the creature later from exile.)