msem-instigator

First strike

{T}: Add one mana of any color.
Augmented — Whenever a nontoken creature you control enters, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on it.

Whenever a token creature you control dies, each opponent loses 2 life.

Whenever you draw a card, you may exile the top card of your library.
{3}{U}{U}, Sacrifice Collector of Memories: Shuffle your hand into your library, then put each card exiled with Collector of Memories into its owner's hand.

Creatures you control named Colocolo can't be blocked and have ward {2}.
{U}{U}: Put an inspiration counter on target creature. It's named Colocolo in addition to its other names for as long as it has an inspiration counter on it.

Reach
When Colonial Effigy dies, create a 1/1 white Spirit creature token with flying.

Shimmer (Whenever this creature attacks, create a tapped and attacking token that's a copy of it. Exile the token at the beginning of the end step.)
When Colpah Mystic enters, you may discard a card. If you do, creatures you control named Colpah Mystic get +2/+2 until end of turn.

Whenever Combat Technician attacks, create a 1/1 colorless Servo artifact creature token that's tapped and attacking. Then Combat Technician gets +1/+1 until end of turn for each artifact you control.

Whenever one or more creatures you control with counters on them attack, draw a card.

Flash
When Commanding Princess enters, choose two —
• Commanding Princess deals 2 damage to any target and you gain 2 life.
• Return target permanent card with mana value 2 or less from your graveyard to your hand.
• Destroy target artifact or enchantment.
• Create a 1/1 colorless Shapeshifter creature token with changeling.

Adorned — Commoners' Favored gets +2/+2 as long as it's equipped and/or enchanted.

Discard a card: Concealed Slasher gets +1/+1 until end of turn and can't be blocked this turn.

{T}: Conchspear Hunter deals 1 damage to any target. Activate only if you control three or more artifacts.

When Conduit of the Conflux enters, scry 2.
{T}: Add one mana of any color.

At the beginning of combat on your turn, you lose 1 life and rouse 1. (Put a +1/+1 counter on a permanent you control. If it isn't a creature, tap it and it becomes a 0/0 creature in addition to its other types.)

When Conjured Shade dies, target creature you don't control gets -1/-1 until end of turn.

When Conscious Taboo enters, look at target opponent's hand. You may exile a noncreature, nonland card from it. For as long as that card remains exiled, its owner may play it. A spell cast this way costs {2} more to cast.

Whenever another creature you control enters, you gain 1 life.

When Contagious Ghoul dies, target creature an opponent controls gets -1/-1 until end of turn.
Foreshadow {2}{B} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

When Contagious Host dies, each player loses 1 life.
Revive {2}{B} ({2}{B}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Prowess
{1}{U}, Tap an untapped Wizard you control: Target creature gets -3/-0 until end of turn.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)

Landfall — Whenever a land you control enters, Convoy's Companion gets +1/+1 until end of turn. If that land was a Desert, put a +1/+1 counter on it instead.

Hexproof (This creature can't be the target of spells or abilities your opponents control.)

{3}{W}: Tap target creature. Activate only during your turn.