msem-instigator

Whenever Almgrove Spellblade attacks, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Exile the top two cards of your library. Until end of turn, you may play cards exiled by Almgrove Spellblade.

First strike
Whenever you scry, Battlewise Paragon gets +1/+1 until end of turn for each card you looked at while scrying this way.

Flash
When Blade of Mautakesh enters, creatures you control gain poisonous 1 until end of turn. (Whenever those creatures deal combat damage to a player, that player gets a poison counter. Multiple instances of poisonous trigger separately.)

Flying, trample
Whenever Bretala of Redsky attacks, it gains double strike until end of turn unless defending player sacrifices a creature.

First strike
When Petal of a Heart enters, if you cast it, reveal up to two permanent cards with mana value 1 from your hand. For each card revealed this way, conjure a duplicate of that card into your hand.

Burn the Witch deals 3 damage to target creature or planeswalker. If that creature or planeswalker would die this turn, exile it instead.

When Shaidostan Cryoforger enters, exile the top card of your library.
When Shaidostan Cryoforger dies, you may put the exiled card into your hand.

Target opponent reveals their hand. You may choose a noncreature, nonland card from it. If you do, that player discards that card. Otherwise, they lose 3 life.

Counter target spell if you have more cards in your graveyard than that spell's controller.

{2}{B}, {T}, Sacrifice Sculler's Oar: Return up to two target creature cards from your graveyard to your hand.

Poisonous 3 (Whenever this creature deals combat damage to a player, that player gets three poison counters.)
When Soulbreaker of Mautakesh enters, target poisoned player sacrifices a creature.

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
When Aith Aera Sentinel enters, create a 1/1 green Elf creature token.

When Trapped in the Tower enters, exile target creature an opponent controls until Trapped in the Tower leaves the battlefield. (That creature returns under its owner's control.)
When you lose life, sacrifice Trapped in the Tower.

Deathtouch
{T}: Add one mana of any color.

Fiendish Yaoguai can't block.
Scavenge {5}{B} ({5}{B}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

Choose a Function added to Rapid Recursion. Create a Function token with those effects. (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)
Draw a card.

Discard your hand. Creatures you control get +X/+0 and gain first strike until end of turn, where X is the number of cards discarded this way.

Reach
{2}{G}: Rei's Ranger gets +2/+0 until end of turn.

Deathtouch
Infiltrate (Whenever one or more attacking creatures you control aren't blocked, this creature gets +1/+1 until end of turn.)

Enchant creature
Enchanted creature is a Horror with base power and toughness 3/3 and loses all other creature types and abilities.
Whenever enchanted creature deals combat damage to a creature, create a token that's a copy of Plagas Infestation and attach it to the damaged creature.

When CySec Moderation Council enters, choose a nontoken enchantment you control or an enchantment card in your graveyard. Conjure a duplicate of that card into your hand.

{T}, Sacrifice Camahueto Calf: Return target land card from your graveyard to the battlefield.

Flying, lifelink
Legendary creatures you control get +1/+1.

Aleud Scorn deals 3 damage to target creature.
At the beginning of your upkeep, you may exile Aleud Scorn from your graveyard. If you do, add {R}{R}.

Bleed—{B}, Pay 2 life. (You may cast this spell for its bleed cost if an opponent has lost life this turn.)
Draw two cards, then discard a card.