msem-instigator

Enchant player
At the beginning of each end step, create X 1/1 green Snake creature tokens, where X is the amount of life enchanted player lost this turn.

Choose two —
• Target player creates two 2/2 white Knight creature tokens with vigilance.
• Destroy target creature with power 4 or greater.
• Target player gains hexproof until end of turn.
• Return target nonland permanent you don't control to its owner's hand.

At the beginning of your upkeep, Bauble of Infinites deals 2 damage to each opponent and you gain 2 life.

Augmented — When Behavioral Specialist enters, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, create a 1/1 blue Elemental creature token with flying.
Whenever one or more creatures you control deal combat damage to an opponent, you may draw a card. If you do, discard a card.

At the beginning of combat on your turn, target creature you control has base power and toughness 5/5 until end of turn.

Creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, Bellowing Thoctar gets +2/+2 until end of turn.

Aetherize each permanent you control. Exile Beneath the Horizon. (To aetherize a permanent, create a token that's a copy of it, then exile that token.)

At the beginning of your upkeep, mill a card.
Whenever a creature card is put into your graveyard from anywhere, if that card has flying, you may put a flying counter on Berylscale Alaj. Repeat this process for first strike, double strike, deathtouch, hexproof, lifelink, menace, reach, trample, and vigilance.

Trample, haste, indestructible
Whenever a permanent an opponent controls is put into a graveyard from the battlefield, put a +1/+1 counter on target Ooze.

Put a +1/+1 counter on each of up to X target creatures.
Augmented — If you've spent {W}{U}{B}{R}{G} to cast spells this turn, instead put three +1/+1 counters on each of those creatures. They gain trample until end of turn.

When Biohazard enters, destroy all other nonland permanents with mana value X or less.
At the beginning of each end step, each opponent loses life equal to the number of cards they've drawn this turn plus the number of spells they've cast this turn.

Create a 1/1 blue Bird creature token with flying. (Cast a copy of this spell once while this creature is on the battlefield.)

Flying
Whenever Blade of Reckoning deals combat damage to a player, that player sacrifices an untapped permanent.

Advance {1}{R}{W}{B} (Cast this for {1}{R}{W}{B} to advance it as it enters. {1}{R}{W}{B}: Advance this as a sorcery.)
Whenever Blastburn Angel advances, it gets +1/+1 and gains flying until end of turn. It deals 1 damage to each other creature.

({T}: Add {U}, {B}, or {R}.)
Bleak Dominion enters tapped.

Gestalt (When this or another creature you control enters, you may merge it with the one in play, keeping counters and attachments. They become the permanent on top plus all abilities from under it.)
This permanent gets +2/+2 for each card and token merged with it.

Whenever one or more creatures an opponent controls attack you or a planeswalker you control, that player gets a poison counter.

When Blessing of Roya enters or whenever you cast a spell from a graveyard, you gain 5 life and you mill five cards. Then you may put a card from your graveyard on the bottom of your library.

Whenever you cast an instant or sorcery spell from exile, copy it. You may choose new targets for the copy.

Haste
Augmented — Whenever you cast a spell, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on Bolstered Guardian. It loses this ability and gains “Whenever this attacks, it deals 2 damage to each of up to two targets.”

You may cast a spell with mana value 3 or less from your hand without paying its mana cost. (Then exile this card. You may cast the creature later from exile.)

Archive 5 (As this enters, shuffle the top five cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever a player discards a card, draw a card from the archived library.

[+2]: Discard a card at random. If you do, draw two cards.
[0]: Target creature's controller may pay X life. If they don't, you lose X life and gain control of it (Choose any number for X.)
[–3]: Flip a coin until you lose a flip or choose to stop flipping. For each flip you won, draw two cards and create a tapped Treasure token.

When Brand New Species enters, create a tapped 3/2 green Horror creature token.
Augmented — At the beginning of each end step, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on up to one target Horror you control.

Whenever you attack or cast a multicolored spell, put a +1/+1 counter on Brandy Axel.
If Brandy Axel would be destroyed, remove a +1/+1 counter from her. If you do, instead remove all damage from her and she deals 2 damage to each opponent.