msem-instigator

Whenever you cast a black spell, put a +1/+1 counter on Flenser's Lieutenant.
{B}{B}: Return Flenser's Lieutenant from your graveyard to your hand.

Whenever a creature an opponent controls dies, monstrosity 1. (If this creature isn't monstrous, put a +1/+1 counter on it and it becomes monstrous.)

Deathtouch
When Flesheater Vine enters, you may have it consume. If you do, put a +1/+1 counter on it and you gain 3 life. (To consume, sacrifice another creature or exile a creature card from your graveyard.)

Whenever Fleshwarper or another Horror you control dies, each opponent loses 1 life and you gain 1 life. You may mill a card.

When Fleshwrithe Ghoul enters, each player sacrifices a creature.
Revive {4}{B} ({4}{B}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Flash
Flying
Whenever another Spirit you control enters, put a +1/+1 counter on Flickers in the Night.

Flooding Magma deals 2 damage to each creature except for equipped creatures you control.

Flying
Menagerie — At the beginning of combat on your turn, if there are five or more creature types among creatures you control, create a 1/1 black Insect Spirit creature token with flying and you gain 1 life.

(Add a quest counter as this enters. Sacrifice after 3.)
At the beginning of your end step, if you have more life than an opponent, add a quest counter.
Mill two cards. You may put one of those cards into your hand. If you do, you lose 3 life. Otherwise, you gain 3 life.
Return target creature or planeswalker card from your graveyard to the battlefield.

Destroy target attacking or blocking creature. Flurry of Bolts deals 1 damage to each other attacking or blocking creature that creature's controller controls.

Permanents you control gain hexproof and indestructible until end of turn.
Prevent all damage that would be dealt to you this turn.
You gain hexproof until end of turn.

Creatures your opponents control get -1/-1 until end of turn. (Then exile this card. You may cast the creature later from exile.)

When Flying Throne enters, attach it to target creature you control.
Equipped creature gets +1/+0 and has flying.
Equip {2}

Archive 6 (As this enters, shuffle the top six cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever one or more Dragons you control attack, you may cast the top card of the archived library without paying its mana cost.

Create a 2/2 red Dragon creature token with flying and haste.
Whenever a nontoken Dragon you control attacks, you may return Flynn's Wonder from your graveyard to your hand.

[+1]: Create a 1/1 blue Dragon creature token with flying and “This creature can't attack unless you control a nontoken Dragon.”
[–2]: Flynn deals damage to target creature or planeswalker equal to the total power of Dragons you control.
[–5]: You get an emblem with “Dragon spells you cast cost {U}{R} less to cast and have flash.”

Draw three cards, then put a card from your hand on the bottom of your library.

Sacrifice a creature: Harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Look at the top two cards of your library. Put any number of them into your graveyard and the rest back on top in any order.

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Prevent all combat damage that would be dealt this turn.

Whenever a Plains you control enters, create a 1/1 white Soldier creature token.
Whenever you attack, you may search your library for a Plains card, reveal it, put it into your hand, then shuffle.

Whenever Font of Natural Essence enters or is put into a graveyard from the battlefield, create two 1/1 green Saproling creature tokens.

{T}: Each opponent loses 1 life.
Whenever you cycle a card or cast a spell with a cycling ability, untap Font of Nefarox.

Counter target monocolored spell.

Once each turn, when you cast an instant or sorcery spell, you may exile the top two cards of your library if you cast it for its showcase cost, otherwise, look at the top two cards of your library, then put one on the bottom of your library and exile the other. You may play cards exiled this way until you exile one or more other cards with For the Court of the Queen.

Destroy target nonland permanent with mana value less than or equal to the number of cards in your graveyard.