msem-instigator

Destroy target artifact.
Reprise {R} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Target creature gets +3/+3 until end of turn.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Concord — As long as there are four or more card types among permanents you control, Bubbledome Waveblade gets +1/+1.

Target creature gets +2/+2 until end of turn. If it's an artifact creature, it gains indestructible until end of turn.

Target attacking creature gets +3/+3 until end of turn. If it's an artifact creature, it gains trample until end of turn.

{T}, Sacrifice a creature: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
{T}, Sacrifice a Clue: Create a 3/3 green Elemental creature token.

Target creature gets +2/+0 and gains haste until end of turn.
Flashback {1}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Target creature or planeswalker you control explores. (Reveal the top card of your library. Put it into your hand if it's a land. Otherwise, put a +1/+1 or loyalty counter on that permanent, then you may put that card into your graveyard.)

Create a 1/1 colorless Construct Actor creature token. Put a +1/+1 counter on it if you control another Construct.
Compose (Then if you cast this from your hand, exile it and create a Saga token with “III—You may cast a copy of this card from exile without paying its mana cost.”)

Exile target nontoken creature. That creature's controller creates X 1/1 red and white Warrior creature tokens, where X is that creature's mana value.

First strike
Whenever you make first contact, Callous Conduit deals 1 damage to target player or planeswalker. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)

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

Enchant creature you control
Enchanted creature gets +1/+1 and has ward {1}.
Whenever enchanted creature deals combat damage to a player, choose target creature you control without a permanent named Candlegift attached to it. Create a token that's a copy of Candlegift attached to that creature.
{W}, Sacrifice five enchantments: Create a 5/5 white Angel creature token with flying.

You may cast this spell with no targets for {2}{R}. If you do, as it resolves, create a 1/1 red Hound creature token, then attach Canine Acumen to that token.
Enchant creature
Enchanted creature gets +2/+0 and has first strike.

Haste
Whenever Carnival Daredevil deals combat damage to a player, exile the top card of your library.
Duet — You may play cards exiled with Carnival Daredevil as long as you control exactly two tapped creatures.

Flying
When Carrier Familiar enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

Flying
When a creature scavenges Carrion Courier, put a flying counter on that creature.
Scavenge {2}{B} ({2}{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.)

Target attacking creature gets +3/+1 until end of turn.
Conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

Whenever another creature or enchantment enters the battlefield under your control, you gain 1 life.
{3}{W}{W}, Pay 5 life: Castigated Sister becomes a 5/5 Angel Horror with flying. (This effect doesn't end at end of turn.)

Haste
Caulte Axeslinger gets +2/+2 as long as any opponent lost exactly 3 life this turn.

{1}{G}, Sacrifice Caustic Caterpillar: Destroy target artifact or enchantment.

When Caustic Lurker dies, target player loses 1 life.

Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)
Whenever you cast a spell, if its mana value is less than Cavorting Beauty's power, remove a +1/+1 counter from Cavorting Beauty.

Whenever a Soldier or Knight enters the battlefield under your control, you may sacrifice Ceanne's Dawnbringer. If you do, put your choice of two different counters on that creature from among +1/+1, first strike, lifelink, and vigilance.

Once each turn, when you sacrifice a permanent, you may put two progress counters on Ceaseless Research and surveil 2.
{2}{G}, Remove X progress counters from Ceaseless Research: Create an X/X green Mutant creature token. X can't be less than 3. Activate only as a sorcery.