msem-instigator

Attentive Glider gets +2/+2 and has flying as long as you cast an Adventure spell or a permanent you controlled explored this turn.

(Add a quest counter as this enters. Sacrifice after 3.)
At the beginning of your end step, if you cast no spells this turn, add a quest counter.
Untap each creature you control. Until your next turn, they gain “{T}: Scry 1.”
Scry 2, then draw two cards. You gain 2 life.

When Attuned Ancient enters, if you control a legendary creature, you may have Attuned Ancient deal damage equal to its power to target creature an opponent controls.

Haste
Augmented — When Attuned Lifeform enters, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on each creature you control. They gain vigilance until end of turn.

Prowess
Other Monks you control get +1/+1.
Whenever you cast a spell during another player's turn, untap each Monk you control.

Haste
Augmented — At the beginning of combat on your turn, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, gain control of target nonland permanent until end of turn. Untap it. It gains haste until end of turn.

Tribute 3 (As this creature enters, an opponent of your choice may put three +1/+1 counters on it.)
When Atuum Serpent enters, if tribute was paid, it gains defender. (This effect lasts indefinitely.)

{1}, Sacrifice a creature or enchantment: Exile the top card of your library. You may play that card this turn.

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

Flying
Whenever August Sunbird attacks, create a token that's a copy of another target creature you control, except it's 1/1, and it's tapped and attacking. Sacrifice the token at the beginning of the next end step.

Enchant creature
When Aura of Leadership enters, create four 1/1 white Human Soldier creature tokens.
Enchanted creature gets +2/+2.

Counter target creature spell. Scry 2.
Foresee — As you draw Aurora's Whisper, you may reveal it and pay {U}. When you do, return target creature with mana value 3 or less to its owner's hand.

Exile target tapped creature. Its controller gains 3 life.

When Automated Blademaster enters, create a colorless Equipment artifact token named Sword with “Equipped creature gets +1/+1” and equip {1} and attach it to Automated Blademaster.

{T}: Add {C}.
{2}, {T}: Add three mana of any one color.

Autumn Ward's power and toughness are each equal to the number of creature cards in your graveyard.
Unveil {2}{B}{G} ({2}{B}{G}: Transform this. Unveil only as a sorcery.)

{T}, Tap an untapped creature you control: You draw a card and you gain 1 life.

When Autumnal Resonants enters, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Create a 3/3 red and green Elemental creature token with haste.

Frenzy 2 (Whenever this creature attacks and isn't blocked, it gets +2/+0 until end of turn.)
Blocked creatures you control have first strike.

{2}: Avaricious Ghul gets +1/+1 until end of turn. If mana from a Treasure was spent to activate this ability, put a +1/+1 counter on Avaricious Ghul instead.

As Avaz Fortress enters, you may pay 1 life. If you don't, Avaz Fortress enters tapped.
Satrapies you control have “{T}: Add {R}.”

(As an Encounter enters, choose an opponent to protect it. You and others can attack it. When defense counters are removed, create a 0/0 Army token if you don't control one, then put that many +1/+1 counters on a Army you control.)
When Avaz Rising enters, return target creature card from your graveyard to the battlefield. That creature becomes an Army in addition to its other types.

Flying
Harmony — Until the end of your next turn, you may cast target instant or sorcery card from your graveyard. If that card would be put into your graveyard, exile it instead.
When Aven Acoustimancer enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Flying
When Aven Merchant enters, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Flying
When Aven Strategist enters, return up to one target creature to its owner's hand.