msem-instigator

Equipped creature gets +1/+0 and has “Whenever this creature becomes tapped, you gain 1 life.”
Equip {2}

Exile target artifact, enchantment, or creature with flying.

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

Forbidding Isle enters tapped unless you control a Swamp.
{T}: Add {U} or {R}.

Destroy target artifact or enchantment. Create a 1/1 green Saproling creature token.

If a spell, ability, or creature an opponent controls would deal 4 or more damage to you or cause you to lose 4 or more life, you lose 4 life instead. (Damage won't be dealt.)

Whenever a player casts a spell, put a doom counter on Foreboding Presence.
At the beginning of each player's end step, if no spells were cast this turn, sacrifice Foreboding Presence. It deals damage equal to the number of doom counters on it to that player.

As Foreboding Ruins enters, you may reveal a Swamp or Mountain card from your hand. If you don't, Foreboding Ruins enters tapped.
{T}: Add {B} or {R}.

{2}, Exile a card with a cycling ability from your graveyard: Draw a card.
Cycling {3}{G} ({3}{G}, Discard this card: Draw a card.)
When you cycle Foregone Ancestries, you may exile it. If you do, return target card with a cycling ability from your graveyard to your hand.

When Forerunner of the Briar enters, sacrifice two lands. When you do, choose one —
• Create a 3/3 green Beast creature token.
• Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

You may put a creature or land card from your hand onto the battlefield. Then each opponent may put a permanent card from their hand onto the battlefield. If one does, you may repeat this process.

Forest Fire deals 4 damage to target creature or planeswalker. (Then exile this card. You may cast the creature later from exile.)

When Forest Whale dies, put a number of +1/+1 counters on target creature you control equal to Forest Whale's power.

Hexproof

Forestheart Elemental enters with a +1/+1 counter on it for each land you control.

Target creature gets +2/+2 until end of turn. If you cast this spell from exile, that creature gets +4/+4 and gains trample until end of turn instead.
Prophecy {G} (Once each turn, you may exile a card with prophecy as you reveal it. When you do, you may cast it for its prophecy cost as long as it's exiled.)

Heroic — Whenever you cast a spell that targets Forge Adept, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
{6}{R}: Create a 3/3 colorless Golem enchantment artifact creature token. If mana from an artifact was spent to activate this ability, that token gains haste.

Search your library for two land cards and reveal them. If you attacked this turn, put them onto the battlefield tapped. Otherwise, put them into your hand. Then shuffle.

Choose one —
• Forge Trick deals 3 damage to target creature.
• Target creature gets +3/+0 until end of turn.

Attacking creatures you control have “{R}: This creature gets +1/+0 until end of turn.”
Armed — Whenever Forgeborn Barbarian attacks, add {R} for each equipped creature you control.

Whenever you cast an artifact spell, create a 1/1 colorless Construct artifact creature token.

Choose one —
• Forgemaster's Charm deals X damage to target creature.
• Destroy X target artifacts.
• Create an X/X colorless Juggernaut artifact creature token.

Search your library for an Equipment card, reveal it, put it into your hand, then shuffle.

{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.