msem-instigator

Whenever Recurring Abomination deals combat damage to an opponent, you may put target creature card with mana value 3 or less from a graveyard onto the battlefield under your control.
{4}{B}{B}: Return Recurring Abomination from your graveyard to the battlefield tapped.

Whenever Starfall Instructor attacks, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Each opponent loses 2 life.

Creatures you control get +2/+2.
Lifecycle {3} ({3}, Discard this card: Create two tapped 1/1 colorless Elemental creature tokens.)

When this creature enters, create a Treasure token.
This creature gets +1/+1 for each different name among tokens you control.

Sacrifice a creature: Rapacious Demon gets +1/+1 and gains flying until end of turn. Activate only as a sorcery.

Prowess
When Cramming Student enters, conjure ten cards named Fatigue and shuffle them into your library. (They're colorless sorceries that cost {2} and have “Draw a card.”)
Instant and sorcery spells you cast cost {1} less to cast.

{R}: Draconic Aspirant gets +1/-1 until end of turn.

Destroy target non-Gorgon creature. Scry 1.

{3}, {T}: Each opponent loses 2 life. This ability costs {3} less to activate if you've sacrificed a permanent this turn.

Equipped creature gets +1/+1 and has menace.
Equip {R}

Enchant creature
Enchanted creature gets -3/-0 and can't block.

Identity — Sureshot Recruit has reach as long as you control at least two other creatures that share a creature type with it.

Protection from Dawn Chord (This creature can't be blocked, targeted, dealt damage, or enchanted by anything named Dawn Chord.)
{1}{R}: Target Reflection's base power becomes equal to Dusk Chord's power until end of turn.

Create a token that's a copy of target nonland permanent you control with mana value X.
Flashback—{U}{U}, Exile cards from your graveyard with exactly X card types among them. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Tap up to one target nonland permanent and put a stun counter on it.
Compose (Then if you cast this from your hand, exile it and create a Saga token with “r3—You may cast a copy of this card from exile without paying its mana cost.”)

As an additional cost to cast this spell, you may sacrifice a creature.
Create a 1/1 green Insect creature token. If you sacrificed a creature to cast this spell, create three of those tokens instead.

Equipped creature gets +2/+2.
As long as equipped creature is a Soldier, it has vigilance.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Enchant creature
When Rotten Retinue enters, return target creature card from your graveyard to your hand.
Enchanted creature gets +2/+2 and has deathtouch.

Enchant creature you control
When Thassa's Benefaction enters, scry 2.
Enchanted creature gets +1/+0 and has flying.

Flying
When Rushwater Hunter enters, you may return target creature to its owner's hand.

Lifelink
{W}{B}, {T}: Dusk Rider deals X damage to target attacking creature, where X is the number of Spirits you control.

When Silkweaver Matron enters, create a white Aura enchantment token named Spinning Silk attached to target creature. The token has enchant creature and “Whenever enchanted creature attacks, tap target creature defending player controls.”
{1}{W}: Untap target enchanted creature.

When Shackled Memories enters, return target instant or sorcery card from your graveyard or card with flashback you own from exile to your hand.
Invocation — Whenever you spend four or more mana to cast a spell or activate an ability during your turn, create a 1/1 white Spirit creature token with flying.

This spell costs {1} less to cast for each card in your graveyard.
Arise {9}{B}. This ability costs {1} less to activate for each other card in your graveyard. ({9}{B}, Exile this from your graveyard as a sorcery: Create a black token copy of it that's also a Zombie and can't block.)