msem-instigator

When Forlorn Farmhand dies, create a 1/1 colorless Spirit creature token.

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.)

Forlorn Path enters tapped unless you control one or fewer other lands.
{T}: Add {B} or {G}.
Cycling {2} ({2}, Discard this card: Draw a card.)

({T}: Add {U} or {B}.)
As Forlorn Ruin enters, you may pay {1}. If you don't, Forlorn Ruin enters tapped.

{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.

When Forlorned Knight enters, you may sacrifice another creature. If you do, create two 1/1 white Human creature tokens.
Whenever you attack, if another creature died under your control this turn, creatures you control get +1/+1 until end of turn.
Fleeting {W}{B} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Target creature you control gets +3/+0 and gains lifelink and indestructible until end of turn.

Enchant creature
Enchanted creature has deathtouch and menace.
{G}{U}: Enchanted creature gains hexproof and indestructible until end of turn. Tap it.
{R}: Enchanted creature gets +1/+0 until end of turn.

When Form of the Sunbird enters, it deals 4 damage to each creature. Your life total becomes 4.
If you would lose the game, instead transform Form of the Sunbird.

Exile target creature you control, then each other player may exile a creature they control. Each player who exiled a creature this way reveals cards from the top of their library until they reveal a creature card with mana value different from the creature they exiled, puts that card onto the battlefield, then shuffles.

Flash
Enchant creature
Enchanted creature has erratic. (When this creature dies, reveal the top four cards of your library. Put a creature card that costs less than this revealed this way onto the battlefield and the rest on the bottom of your library in any order.)

Choose any number of target creature and/or planeswalker cards in your graveyard. Return one of them to the battlefield and put the rest on top of your library in any order.

Defender, trample
Tap any number of other untapped creatures you control with total toughness 8 or greater: Formidable Bulkvine's base power becomes 8 until end of turn and it can attack this turn as though it didn't have defender.

Flying, vigilance
When Formless Eidolon enters, create a tapped token that's a copy of target land you control.
Evoke {3} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Exile all creatures with power 4 or greater.

Flying
Mark (Whenever this creature attacks, mark target creature until end of turn.)
Whenever a marked creature dies, you gain 2 life.

{T}: Add {C}.
{T}, Reappropriate: Add {W} or {B}. (Exile exactly two cards from your hand and/or graveyard.)

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

{T}: Add {B} or {G}. You lose 1 life unless you have less life than an opponent.

Enchant opponent
At the beginning of enchanted player's upkeep, they lose 1 life and each of their opponents gains 1 life.
{4}{B}, Sacrifice Forsaken Shores: Enchanted player loses 3 life and you gain 3 life.

Flying
Whenever a creature in Forsaken Soulherd's pack dies, look at the top card of your library. If it's a creature card with equal or lesser power, you may reveal it and put it into your hand. If you didn't put that card into your hand, you may mill it. (Two or more creatures you control with equal power are in a pack.)

Forsaken Sunseeker gets +1/+1 and has flying as long as it's not your turn.

Equipped creature gets +0/+2 and has flying.
Equip {2}

Fortress Arena enters tapped.
{T}: Add {R} or {W}.
{2}{R}{W}, {T}, Sacrifice Fortress Arena: Draw a card.

Bulwark — At the beginning of each upkeep, if you control a creature with toughness 4 or greater, Fortress Sentinel gains hexproof until end of turn.