msem-instigator

When Mire Sculptor enters, mill three cards.
Whenever you sacrifice a permanent, you may pay {2}. If you do, return target permanent card from your graveyard to your hand.

Flying, deathtouch
Whenever Queen of the Hive deals combat damage to a player, create a 1/1 green Insect creature token for each Insect you control.

Flash
Unveil {3}{B}{G} ({3}{B}{G}: Transform this. Unveil only as a sorcery.)

When Barbarian Intimidator enters, target creature can't block this turn.
When Barbarian Intimidator enters, prevent all combat damage that would be dealt to target creature this turn.

Double strike, vigilance
At the beginning of combat on your turn, create X 1/1 red Dwarf creature tokens with haste, where X is the number of embattled nontoken creatures you control. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

When Dawson's Warden enters, create a Treasure token.
As long as you control three or more artifacts, Dawson's Warden gets +2/+0 and has first strike.

Lifelink
Whenever Painstriker attacks, it deals 2 damage to target creature defending player controls.

Rakkiri Piker has double strike as long as it's embattled. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Whenever another creature you control enters, Sunblessed Orator deals 1 damage to each opponent and you gain 1 life.

Double strike
Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
Engage (This creature must be blocked each combat if able.)

Whenever Warhound Shuja attacks, look at the top three cards of your library. You may put a creature card with mana value less than or equal to Shuja's power from among them onto the battlefield tapped and attacking. Put the rest on the bottom of your library in any order.

Whenever one or more creatures you control deal combat damage to a player or planeswalker, create a Clue token.
{G}{U}, Sacrifice a Clue: Put a +1/+1 counter on target creature. Proliferate.

Flying, vigilance
At the beginning of your end step, if a creature you control dealt combat damage to an opponent this turn, put a +1/+1 counter on Horizon Prophet.

Flying
Whenever another creature you control enters, you may search your library for an instant or sorcery card with the same mana value as that creature, reveal it, put it into your hand, then shuffle.

Whenever an opponent activates an ability of a permanent, if it isn't a mana ability, you gain 1 life and create a Gold token. (It's an artifact with “Sacrifice this artifact: Add one mana of any color.”)

Flying
When Witch of Spring's Promise enters, shuffle any number of cards from your hand into your library, then draw that many cards plus one.

Flash
Flying
When Fang Luo enters, exile target spell or creature an opponent controls with mana value 4 or less, then its owner puts it onto the battlefield face down. (It's a 2/2 creature.)

When Fel Alston, Halfway Queen enters, return target creature card from your graveyard to the battlefield. Then exile that creature unless Fel Alston was cast for its escape cost.
Escape—{1}{W}{U}{B}, Sacrifice two creatures. (You may cast this card from your graveyard for its escape cost.)

When Shadowbinder Touka enters or attacks, exile up to one target creature card from a graveyard.
You may play creature cards exiled with Touka.
Sacrifice another creature: Add two mana in any combination of colors. You can't spend this mana to cast spells from your hand. If this mana is spent to cast a creature spell, that creature enters with a finality counter on it.

Lifelink
Whenever Jerrold, Fugitive or another creature you control enters, if you cast it, you may cast target instant or sorcery card from your graveyard with lesser mana value by paying life equal to its mana value rather than paying its mana cost. Exile that card instead of putting it anywhere else as it resolves.

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 Graide, Voice of Autumn enters, create X 1/1 green Squirrel creature tokens.
Squirrels you control get +1/+0 and have haste.
Nonbasic lands your opponents control enter tapped.

Double strike, trample
Enchantment spells you cast cost {1} less to cast.
Whenever you put a lore counter on a Saga you control, Douglass, Star of the Show gets +1/+1 until end of turn.

When Forebear of Hibernation enters, each player may search their library for a creature card, reveal it, put it into their hand, then shuffle. Then you choose a nonland card name.
Spells with the chosen name cost {2} more to cast.

Lifelink
Rafiq the Magnanimous has double strike as long as it's attacking.
Whenever Rafiq the Magnanimous attacks, if it's enchanted, equipped, or was the target of a spell or ability you controlled this turn, draw a card.