msem-instigator

{T}: Target creature loses all abilities until end of turn. Exile Chochin the Silent Moth and that creature.

Whenever another creature you control enters, you gain 1 life.
{4}{W}: Return another target creature you control to its owner's hand.

Flash
Flying
When Cobblespook enters, tap target artifact or creature an opponent controls.

First strike

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.

When Coralight Mystic enters, create a white Aura enchantment token named Whale's Spirit attached to target creature. The token has enchant creature and “Enchanted creature has lifelink.”

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Curious Cubs has first strike as long as its attacking.
When Curious Cubs has three or more +1/+1 counters on it, remove them all and transform it.

Identity — When Danuri Warcaller enters, if you control at least two other creatures that share a creature type with it, create a 1/1 white Soldier creature token.

{W}, {T}: Target attacking creature gets +1/+1 until end of turn. This ability costs {W} less to activate if it targets a Soldier.

Double strike

Flying
When Delivery Bird enters, if you control an artifact, put a +1/+1 counter on another creature you control.

Lifelink
Sacrifice Devoted Apothecary: Remove a counter from target permanent.

Diligent Believer gets +1/+1 for each +1/+1 counter on other creatures you control.

When Doomed Traveler dies, create a 1/1 white Spirit creature token with flying.

When Dynasty Infantry enters, choose one —
• Search your library for a card named Dynasty Infantry, reveal it, put it into your hand, then shuffle.
• Put a +1/+1 counter on target creature you control.

When Eighth-Life Companion enters, put two +1/+1 counters on target creature you control.
Recite {1}{W} (You may cast this from your graveyard for its recite cost. If you do, exile it when it enters or if it would leave.)
Revive {2}{W}{W} ({2}{W}{W}, 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.)

Double strike
Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)

Flying
When Ephara's Watcher enters, scry 2.

Flying, lifelink

When Escorted Ambassador enters, create two 1/1 white Robot Soldier artifact creature tokens.
Whenever a nonland, nontoken permanent enters, exile it unless it was the first to enter under its controller's control this turn.

Flying (This creature can't be blocked except by creatures with flying or reach.)
Escorted Rider gets +1/+1 as long as you control another creature with flying.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
Creature tokens you control have lifelink.

Vigilance
When Expendable Victim dies, create a 1/1 colorless Construct Actor creature token.

Whenever another Avatar you control enters, upgrade it and Experienced Mentor. (Give each one of the listed counters it doesn't already have. Upgrades are independent.)
• +1/+1
• First strike
• Vigilance

Whenever you gain life, put a +1/+1 counter on Faithful Acolyte.
Faithful Acolyte has lifelink as long as it has four or more +1/+1 counters on it.