msem-instigator

When Bestower of Blooms dies, create an X/X green Plant Knight creature token, where X is Bestower of Blooms's power.

Whenever one or more creatures you control deal combat damage to a player or planeswalker, put a +1/+1 counter on target creature you control.

Sera of Coppercove attacks each combat if able.
Whenever Sera of Coppercove attacks, it fights target creature you don't control.
{1}{R}{G}: Sera of Coppercove gets +3/+3 until end of turn.

At the beginning of your end step, for each opponent, destroy up to one target creature that player controls with power less than or equal to the amount of life that player lost this turn.
{3}{R}: Selezzar, Tyrant of Endak deals 2 damage to each opponent.

Equipped creature gets +1/+0 and has “Whenever this creature deals damage to a player or planeswalker, you may draw two cards. If you do, discard a card.”
Equip {2}

Deathtouch
Whenever Dreadful Gorgon attacks, target attacking creature with lesser power gains deathtouch until end of turn.

Winnow (Damage dealt to this creature also causes you to lose that much life.)
Sacrifice Tormented Echo: Target creature gains winnow until end of turn.

Vigilance
At the beginning of your end step, if you control two or more Spirits and/or creatures with flying, transform Haunted Waif.

Prowess
When Arcane Dredger enters, return target instant or sorcery card from your graveyard to your hand.

Whenever you make first contact, target creature you control can't be blocked by Humans this turn. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)

Reach
{3}{G}: Put a +1/+1 counter on Avaz Sentry.
Surpass {5}{G} ({5}{G}: Transform this creature. This costs {1} less to activate for each counter on it. Activate only as a sorcery.)

Up to two target creatures each get -3/-0 until end of turn. Tap those creatures. They don't untap during their controller's next untap step.

Equipped creature gets +1/+1 and has “{5}, {T}: This creature fights another target creature.”
Equip {5} ({5}: Attach to target creature you control. Equip only as a sorcery.)

Each other nontoken Elf and/or Warrior you control enters with an additional +1/+1 counter on it.
{G}{G}, {T}, Remove two +1/+1 counters from among creatures you control: Create two 1/1 green Elf Warrior creature tokens.

Choose highest or lowest. Target opponent reveals their hand and discards a card with the chosen kind of mana value among the revealed nonland cards.

Lifelink
Whenever you gain life, each opponent loses 1 life.

Double each number and amount of target instant or sorcery spell, activated ability, or triggered ability. Its controller may choose new targets for it. (Amounts are number words, X values, and “a” or “an” used as 1.)

Enchant opponent
When Curse of Bleeding enters, enchanted player loses 2 life.
Enchanted player can't gain life.

Scry X, then purge X times. You lose X life. (To purge, exile two cards that share a type from graveyards. If you do, draw a card.)

As an additional cost to cast this spell, discard two cards.
Target player draws two cards. Return up to one target creature to its owner's hand.

Vigilance, trample
Whenever another Horror you control enters, choose one —
• Destroy target artifact or enchantment.
• You gain 4 life.
• Apex Abomination fights another target creature.

Reach
Whenever Palm Walker or another creature you control enters, you gain 2 life.

Lifelink
Effigy of Morality gets +1/+1 as long as your fealty to Plains is four or greater. (Each Plains you control counts towards your fealty to Plains.)

Choose one or both —
• Counter target spell.
• Exile target permanent you control, then return it to the battlefield under your control.

Sacrifice a creature. Draw cards equal to its power and gain life equal to its toughness. (Then exile this card. You may cast the creature later from exile.)