msem-instigator

Flash
When Commanding Princess enters, choose two —
• Commanding Princess deals 2 damage to any target and you gain 2 life.
• Return target permanent card with mana value 2 or less from your graveyard to your hand.
• Destroy target artifact or enchantment.
• Create a 1/1 colorless Shapeshifter creature token with changeling.

Creatures you control get +1/+1.
When Eternal Purpose enters, exile up to two target creature cards with mana value 3 or less from your graveyard. Return them to the battlefield under your control at the beginning of the next end step.

Creature spells you cast cost {1} less to cast.
Whenever you attack, target attacking creature you control gets +1/+1 until end of turn. If it's legendary, put a +1/+1 counter on it instead.

When Kindled Vengeance enters, if you cast it, create seven 1/1 green Elf creature tokens.
Whenever you attack, Kindled Vengeance deals damage equal to the number of attacking creatures to target creature or planeswalker an opponent controls.

Create two tokens that are copies of target creature you control, except the tokens aren't legendary if the creature is legendary. Those creatures gain haste until end of turn.

At the beginning of combat on your turn, target creature you control gains vigilance until end of turn. That creature can't be blocked this turn.

Whenever an opponent casts their first spell each turn, that player may pay {1}. If they don't, you may create a Treasure token and you may draw a card.

When you cast this spell, copy it for each Dragon permanent you control. You may choose new targets for the copies.
Tyrant's Breath deals 7 damage to target creature or planeswalker.

Destroy target nonland permanent. You may return a card that shares a card type with that permanent from your graveyard to your hand.

When Wildsong Summoner enters, shuffle your library, then reveal cards from the top until you reveal a permanent card. Create a token that's a copy of that card, except it's a 3/3 green Beast creature. Put all cards revealed this way on the bottom of your library in a random order.

First strike, menace
Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
At the beginning of each combat, you may pay {1}. When you do, another target creature gains melee until end of turn. (If a creature has multiple instances of melee, each triggers separately.)

The first instant or sorcery spell you cast each turn has convoke. (Each creature you tap while casting that spell pays for {1} or one mana of that creature's color.)

Whenever Baljurn, the Runelord or another nontoken artifact or enchantment you control enters, create a 0/0 blue Construct artifact creature token. Put a +1/+1 counter on each artifact and/or enchantment creature you control other than Baljurn.

If you would draw a card, you may instead choose creature or land and exile cards from the top of your library until you exile a card of the chosen kind. Put that card into your hand and put all other cards exiled this way on the bottom of your library in a random order.

Deathtouch
Once each turn, when another nontoken creature you control enters, you may sacrifice it. If you do, create a token that's a copy of it except it's a green Dryad in addition to its other types.

Creature spells you cast cost {2} less to cast.
Whenever another nontoken creature you control enters, it becomes a colorless Vehicle artifact with crew 1. (Tap any number of creatures you control with total power 1 or greater: That Vehicle becomes an artifact creature until end of turn.)

When Damaris Alfahir enters, for each opponent, put a bribery counter on an artifact or creature that player controls.
At the beginning of your upkeep, gain control of target permanent with a bribery counter on it until end of turn. Untap it. It gains haste until end of turn.

Flying
Whenever you cast a spell during an opponent's turn, Drosera and Nerium deals 1 damage to each opponent.
As long as Drosera and Nerium is tapped, you may cast spells as though they had flash.

Whenever another creature you control enters, target instant or sorcery card in your graveyard with mana value less than or equal to that creature's power gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

At the beginning of your upkeep, you may put each card in your graveyard on the bottom of your library in a random order, then mill six cards.
During each of your turns, you may play a land and cast a permanent spell from your graveyard.

Whenever a creature card is put into your graveyard from anywhere, it gains revive until the beginning of your next end step. The revive cost is equal to its mana cost increased by {1}. (Pay that card's mana cost increased by {1}, Exile that card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Improve {R} ({R}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
Whenever another creature you control with power less than or equal to Folkvar, Galdurheim Brawler's power attacks, Folkvar deals 1 damage to the player or planeswalker that creature is attacking and you gain 1 life.

When Gharsha, Monstrous Quarry enters, each opponent creates a 1/1 green Elf creature token.
Whenever a creature you control becomes blocked, you may pay {1}. If you do, put a +1/+1 counter on that creature.

Whenever you cast an instant or sorcery spell, create a Treasure Clue token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color” and “{2}, Sacrifice this artifact: Draw a card.)

Flying, trample, haste
Dragons you control get +3/+3 as long as you control permanents with total mana value 20 or greater.
Whenever you spend five or more mana to cast a spell or activate an ability, create a 2/2 red Dragon creature token with flying.