msem-instigator

Defender (This creature can't attack.)
Whenever you cast a spell, if it isn't your main phase, Serene Meditant loses defender until the beginning of your next end step.

Flying
When Sharp-Eyed Wingmate enters, you may return target creature to its owner's hand.

Whenever a player casts an instant or sorcery spell from their hand, you may exile that card as it resolves instead of putting it anywhere else.
Whenever Skill Sketcher attacks, you may cast a card exiled with it. That spell costs {X} less to cast, where X is Skill Sketcher's power.

{1}{U}: Skysail Rigger voyages. (If it isn't blocking or targeted by another spell or ability, it phases out.)
Whenever Skysail Rigger phases in, put a flying counter on it.

Whenever Skysworn Savior attacks, you may return another creature you control to its owner's hand. If you do, Skysworn Savior gets +2/+2 and gains flying until end of turn.

Vanguard — Whenever a creature you control attacks alone, you may exile target instant or sorcery card from your graveyard. If you do, you may cast that spell from exile until your next turn. If that spell would be put into a graveyard, exile it instead.

Beckon Drake {2}{U}{U} ({2}{U}{U}: This noncreature Deity permanently becomes a Drake creature in addition to its other types.)
Flying
Other creatures you control with flying get +1/+1.

Whenever Supreme Mechanothurge or another artifact you control enters, up to one target artifact you control becomes a copy of another target artifact or creature you control, except it's an artifact in addition to its other types.

Flying
Whenever Swiftwing Sphinx or another creature with flying deals combat damage to an opponent, put a +1/+1 counter on that creature.

Flying
Other creatures you control with flying get +1/+1.

Flying
When Thunder Shrike enters, choose up to two target permanents. For each of those permanents, you may tap or untap it.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast your first instant or sorcery spell each turn, copy that spell. You may choose new targets for the copies.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
{3}{U}: Target creature gains slipstream until end of turn.

Flying
When Windrider Elemental enters, target creature gains flying until end of turn.

Deathtouch
Abyss Surger enters with X +1/+1 counters on it, where X is the greatest power among creature cards in your graveyard.

{2}{B}, {T}, Discard a card: Create a 2/2 black Zombie creature token. If a noncreature card was discarded this way, that token enters tapped.

When Asking Imp enters, an opponent may pay 2 life. If they do, return Asking Imp to its owner's hand.

Deathtouch
Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] You may sacrifice another creature. If you do, draw a card.
[Lore III] Remove all lore counters from Astral Leech. Each opponent sacrifices a creature.

Flying
When Augur of Bleak Horizons enters, you gain 3 life and you mill three cards.

Flash
When Axom enters, remove up to three counters from target permanent.
{2}{U}: Return Axom to its owner's hand.

Mark (Whenever this creature attacks, mark target creature until end of turn.)
Whenever Backalley Silencer deals combat damage to a player, destroy target marked creature.

Wither (This deals damage to creatures in the form of -1/-1 counters.)
Whenever Barrow Banshee deals combat damage to an opponent, that player discards a card at random.

When Blood Jade Prophet enters, reveal the top three cards of your library. For each card revealed this way, you may pay 3 life. If you do, put that card into your hand. Otherwise, put it into your graveyard.

Flash (You may cast this spell any time you could cast an instant.)
When Bloodhunter Orca enters, target opponent sacrifices a creature that was dealt damage this turn.

Flash
This spell costs {2} less to cast if five or more cards are in your graveyard.