msem-instigator

Whenever Wandering Doyen is dealt damage, it deals that much damage to you.
{4}{R}: Attacking creatures you control get +1/+0 and gain first strike until end of turn.

Haste
When Collapsing Star Viper enters, you may tap target permanent with mana value X or less.
At the beginning of your upkeep, return Collapsing Star Viper to its owner's hand.

First strike
Prevent all damage that would be dealt to creatures you control by sources with greater mana value.
{2}{W}{W}: Create a 1/1 colorless Construct Actor creature token. Put a vigilance counter on it.

Assault {1}{B} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
Whenever a creature you control assaults, you may have target creature get -2/-2 until end of turn.

Whenever Crescent Crasher attacks, put a +1/+1 counter on target attacking creature with lesser power.

Flying, vigilance
When Guardian Grotesque dies, return up to one target nonland permanent to its owner's hand.
Foreshadow {6} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

{T}: Add {C}.
{1}, {T}: Add {W}{B}.

When Ziggurat Behemoth enters, target creature gets +3/+3 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

{T}: Add {G}. If there are three or more creature cards in your graveyard, add {G}{G} instead.

Scry 3. (To scry 3, look at the top three cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

Vigilance
{1}{W}: Barbarian Axe Flinger gains double strike until end of turn.

Disgraced 2 (This enters with two -1/-1 counters. Whenever it deals combat damage to a player, remove all -1/-1 counters from it.)
Whenever Madame Deficit attacks, you may tap target creature.

Whenever an opponent casts a spell, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Spells your opponents cast cost an additional 2 life to cast until your next turn.

Return target nonland permanent to its owner's hand. Then you may pay {U}{U}. If you do, copy Resonating Force and you may choose new targets for the copy.

Thicketed Path enters tapped unless you control one or fewer other lands.
{T}: Add {G} or {W}.
Cycling {2} ({2}, Discard this card: Draw a card.)

I, II — Put a +1/+1 counter on target creature you control.
Discovery — Creatures you control with +1/+1 counters on them have lifelink.

Double strike
Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
Engage (This creature must be blocked each combat if able.)

Whenever an enchantment you control enters, draw a card. This ability triggers only once each turn.
As long as you control three or more enchantments, Nykthos Enchantress gets +2/+2 and has vigilance.

When Soulblade enters, exile target creature card with mana value 3 or less from your graveyard.
Whenever equipped creature attacks, create a token that's a copy of a card exiled with Soulblade that's tapped and attacking. Exile the token at end of combat.
Equip {1}

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)
Brazen Chimera can't be blocked except by three or more creatures as long as it has a +1/+1 counter on it.

Improve {R} ({R}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
Whenever another creature you control with power less than or equal to Folkvar, Galdurheim Brawler's power attacks, Folkvar deals 1 damage to the player or planeswalker that creature is attacking and you gain 1 life.

When Wistful Fox enters, reveal the top eight cards of your library. You may put a creature card from among them into your hand. Put the rest on the bottom of your library in a random order.

Target creature gets -2/-2 until end of turn. Scry 1.

As an additional cost to cast this spell, tap an untapped artifact or creature you control.
Up to three target creatures can't block this turn.

Whenever a nontoken creature you control enters, if it shares no creature types with other creatures you control, draw a card.