msem-instigator

When Fodder Goblins enters, create a 1/1 red Goblin creature token.

When Folded Fan Recruit enters, invigorate 1. (Choose a creature with the least power among creatures you control and put a +1/+1 counter on it.)

Defender
Foliage Hunter has deathtouch as long as you've cast a spell this turn.

{1}{U}, {T}: Draw a card, then discard a card. You get a glory counter. (You lose glory counters before life. A player with ten or more glory counters wins the game.)
{U}, {T}: Draw a card. Only activate this ability if you are glorious.

{G}, {T}: Add {C}{C}.

{T}, Sacrifice Forgewatcher: Add two mana of any one color. If that mana is spent on a creature spell, it gains haste until end of turn.

Forgotten Experiment can't be blocked.

({T}: Add {B}.)
Forgotten Pit enters tapped.
Deathtouch
{2}{B}{B}: Forgotten Pit becomes a creature in addition to its other types until end of turn.

When Forgotten Wretch enters, you may sacrifice another creature. If you do, draw a card.

When Forlorn Murklurker dies, submerge the top card of your library. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

{1}{G}, {T}, Sacrifice another nontoken creature: Create two tokens that are copies of the sacrificed creature, except they're 0/1. Activate only as a sorcery.

Whenever you cast a noncreature spell, each opponent loses 1 life and you gain 1 life.

Flying
When Foul Drifter enters, target creature gets -1/-1 until end of turn.

{3}, Sacrifice another artifact: Put two +1/+1 counters on Foundryborn Ingester.
When Foundryborn Ingester dies, you may exile it. If you do, return target artifact card from your graveyard to your hand.

Deathtouch
Attacking creatures you control with deathtouch get +2/+0.

When Frantic Efreetspeaker enters, you may discard a card. If you do, draw a card.
{2}, Exile Frantic Efreetspeaker from your graveyard: Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

{T}, Exile a card from your graveyard: Scry 1.

Flying
Whenever Frenzied Sylph attacks or blocks, you may pay {R}. If you do, it gets +3/+0 until end of turn. Exile it at the beginning of the next end step.

{2}{U}: Each player mills three cards.
{3}{B}, Discard a card: Return target creature card from your graveyard to your hand. Proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

Whenever you sacrifice another permanent, Fretport Mob gets +1/+1 and gains haste until end of turn.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, Frilled Drakeling gains menace until end of turn.

Ward {2}
As long as you control six or more lands, Frondpond Errand-Runner gets +2/+0 and can't be blocked.

Improve {G} ({G}: 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.)
When Frontier Trackers dies, create a 1/1 green Elf creature token.

Improve {W} ({W}: 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 Frontier Wayfinder attacks, untap each other creature you control.

Flying
{T}: Add {C}. Spend this mana only to cast spells or activate abilities during an opponent's turn.