Flying
When Marbled Messenger enters, draw a card.

Sacrifice a Treasure: Put a loyalty counter on Marilye, Dreaming Big.
[+1]: Draw a card, then discard a card. If you discarded a nonland card this way, create a tapped Treasure token.
[–3]: Gain control of target artifact. It becomes a Treasure artifact, loses all other types, and loses all abilities except for activated mana abilities.
[–8]: Target opponent chooses a nonland permanent they control. You gain control of the rest.

When Masked Duo enters, tap up to one target creature. If you control an artifact, that creature doesn't untap during its controller's next untap step.

Choose a number between 0 and 5. Counter up to one target spell unless its controller pays {X}, where X is the chosen number. Then mill five minus X cards. You may return a card milled this way to your hand.

Create two 1/1 blue Wizard creature tokens with prowess.

Whenever you draw your second card each turn, scry 1 then put a +1/+1 counter on Melancholic Oracle.

Target artifact or creature's owner puts it on the top or bottom of their library.
Flashback {5}{U}{U}

Flying
{5}: Draw a card. Activate only if your devotion to blue is three or greater.

Return target creature or enchantment to its owner's hand. If that permanent's controller has eight or more cards in their graveyard, its owner puts it on the top or bottom of their library instead.

Tap up to two target creatures. Put a stun counter on each of them.

Whenever Music Master attacks, you may pay {U}. If you do, put a curio counter on another target creature you control.
{1}{U}: Target creature gains flying until end of turn.

Flying
Creatures you control but don't own get +1/+1 and have flying.
Whenever a creature you control deals combat damage to a player, you may return it to its owner's hand.

Flash
Flying
Other creatures you control with flying get +1/+0.

Gain control of target nonland permanent until end of turn. Untap it. Then you may pay {2}. If you do, gain control of that permanent until the end of your next turn.

Enchant creature
Enchanted creature has “Whenever this creature deals combat damage to a player or planeswalker, scry 1, then draw a card.”

Look at the top X cards of your library, where X is one plus the number of differently named lands you control. Put up to three of them into your hand and the rest on the bottom of your library in a random order.

Whenever an enchantment you control enters, each opponent mills two cards.

Flash
When Omen of Deception enters, counter target spell unless its controller pays {2}.
{2}{U}, Sacrifice Omen of Deception: Scry 2.

Whenever Opal-Eye Allseer enters or you cast a noncreature spell, create a 1/1 white Bird creature token with flying.
Wander—{1}{U}, Exile two instant and/or sorcery cards from your graveyard.

Whenever you spend at least five mana to cast a spell, untap Opal-Eye Runeweaver.
{T}: Untap another target permanent not named Opal-Eye Runeweaver. Activate only as a sorcery.

When Opulent Roughrider enters or leaves the battlefield, surveil 1, then you may reveal the top card of your library. If that card has the same name as a permanent you control or a card in your graveyard, put it into your hand.
Wander {4}{U}{U}

Vigilance
Whenever you attack, bless target creature.

Enchant creature
Whenever enchanted creature attacks, put a +1/+1 counter on it. Then if it has three or more +1/+1 counters on it, sacrifice Ordeal of Ephara.
When you sacrifice Ordeal of Ephara, return up to two target nonland permanents to their owner's hand.

Counter target spell. That spell's controller reveals their hand. Choose any number of nonland cards from it. That player puts those cards on the bottom of their library in any order, then draws that many cards.

Flying, ward {1}
Parapet Awakener's power is equal to the number of creatures you control with flying.
{4}{U}: Create a 1/1 blue Gargoyle artifact creature token with flying for each nontoken creature you control with flying.