msem-instigator

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

Whenever Font of Strength enters or is put into a graveyard from the battlefield, target creature you control gets +3/+3 until end of turn.

Counter target permanent spell.

As Forgotten Idol enters, choose a card name.
Spells with the chosen name can't be cast.
{2}, Exile a card with the chosen name from your hand: Exile Forgotten Idol, then each player draws a card. Any player may activate this ability.

Whenever Forgotten King's Mask enters or equipped creature dies, attach it to target creature you control.
Equipped creature has base power and toughness 5/5 and is a Noble in addition to its other types.
{1}{R}, Discard two cards: Create a 1/1 white Human creature token and attach Forgotten King's Mask to it. Activate only as a sorcery.

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

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.)

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.)

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.

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.

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.)

Flash
Enchant creature
Enchanted creature has base power and toughness 0/1 and loses all abilities and creature types.
{2}{U}: Return Fractured Persona to its owner's hand.

Once each turn, if you would draw a card, you may skip that draw. If you do, create a tapped 3/2 colorless Horror creature token.

When Frontline Veteran enters, you may sacrifice another creature or artifact. If you do, draw a card.

Voracious 2 (As this enters, you may sacrifice up to two artifacts and/or creatures. This creature enters with that many +1/+1 counters on it.)
Trample
At the beginning of your end step, if a creature died under your control this turn, create a 1/1 green Saproling creature token.

Target creature gets -1/-1 until end of turn. Create a 1/1 green Saproling creature token.

Gangling Titan has menace and deathtouch as long as there are four or more card types among cards in your graveyard.

{1}, Sacrifice Gasoline Canister: It deals 1 damage to any target. If a creature or planeswalker dealt damage this way would die this turn, exile it instead.

Whenever another creature you control enters, put a +1/+1 counter on each creature you control with lesser power or lesser toughness than that creature.

When Generous Hermit dies, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Return target creature card from your graveyard to the battlefield. If you control a Demon, each opponent loses 3 life.

Destroy target creature or planeswalker. If a planeswalker is destroyed this way, search its owner's graveyard, hand, and library for any number of cards with the same name as that card and exile them. Then that player shuffles.

Creatures you control have deathtouch as long as they're attacking.
[+1]: Target creature you control must be blocked this turn if able.
[–2]: Create two 1/1 white Human creature tokens.
[–X]: Destroy target artifact or enchantment with mana value X and all other permanents with the same name as that permanent.

{T}: Add {C}.
{T}, Sacrifice Ghost Quarter: Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

At the beginning of combat on your turn, you may exert an untapped creature you control with power 4 or greater. If you do, attach Giant's Blade to that creature. (An exerted creature won't untap during your next untap step.)
Equipped creature attacks each combat if able.
Equipped creature gets +2/+0 and has haste.
Equip {3}