msem-instigator

Flying, vigilance
When you attain Unfallen Angel, target opponent discards a card.

{T}: Add {B} or {G}. You lose 1 life.

Flash
First strike
When Imposing Databdara enters, return each other creature with toughness less than or equal to the number of Satrapies you control to their owners' hands.

Elemental Envelopment enters with X +1/+1 counters on it.
When Elemental Envelopment enters, if you controlled a green legendary creature or planeswalker as you cast it, search your library for any number of Elemental creature cards with total mana value X or less, where X is Elemental Envelopment's power, put them onto the battlefield, then shuffle.

Artifact spells you cast cost {1} less to cast.
{2}, Sacrifice an artifact: Target creature gains deathtouch until end of turn.

{2}{B}, Sacrifice Innocuous Sidekick and another creature: Create a 4/4 black Horror creature token with menace. Activate only as a sorcery.

Destroy all creatures. Each player shuffles their graveyard into their library.

If a source you control would deal exactly 1 damage to a permanent or player, it deals 3 damage instead.

Vigilance
{X}{G}, {T}: Ylda, the Wild Soul becomes a copy of target creature you control with mana value X, except it has this ability and vigilance. Activate only as a sorcery.

Whenever one or more creatures you control deal combat damage to a player or planeswalker, create a Clue token.
{G}{U}, Sacrifice a Clue: Put a +1/+1 counter on target creature. Proliferate.

Golden Company Valiant can block any number of creatures.
At the beginning of combat on each opponent's turn, Golden Company Valiant gets +1/+1 until end of turn for each creature that player controls.

At the beginning of each upkeep, untap up to two target lands.

Untap target creature you control. It gains hexproof until end of turn.

[+1]: Exile up to one other target nonland permanent. As long as it remains exiled, its owner may pay {1} as a sorcery to put it onto the battlefield.
[–3]: Choose 0, 1, or 2. Each player sacrifices that many creatures.
[–4]: You get an emblem with “If a nonland, nontoken permanent would enter and it wasn't cast, you may exile it instead.”

You gain hexproof until end of turn.
Prevent all damage that would be dealt to you this turn.

Menace (This creature can't be blocked except by two or more creatures.)

Flash
When Stalker in the Mist enters, up to one target creature gets -1/-0 until end of turn.

Whenever Haunting Maestro attacks, you may tap or untap up to two target creatures.

Whenever another creature you control enters, you may change Declan, Wayward Squire's base power and toughness to that creature's power and toughness until end of turn.

When Holy War enters, create three 1/1 white Cleric creature tokens.
Creature tokens you control have first strike and lifelink.

When Hisana-no-Oni enters, gain control of target creature until Hisana-no-Oni leaves the battlefield.

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.

Deathtouch

Unwavering Questant can't block.
When an opponent fails a trial, return Unwavering Questant from your graveyard to the battlefield.

Enchant creature
Enchanted creature has flying and can only block creatures with flying.