Thistledown Duo

Whenever you cast a white spell, this creature gets +1/+1 until end of turn.
Whenever you cast a blue spell, this creature gains flying until end of turn.

Steel of the Godhead

Enchant creature
As long as enchanted creature is white, it gets +1/+1 and has lifelink. (Damage dealt by the creature also causes its controller to gain that much life.)
As long as enchanted creature is blue, it gets +1/+1 and can't be blocked.

Apostle's Blessing

({W/P} can be paid with either {W} or 2 life.)
Target artifact or creature you control gains protection from artifacts or from the color of your choice until end of turn.

Azorius Knight-Arbiter

Vigilance
This creature can't be blocked.

Heliod's Pilgrim

When this creature enters, you may search your library for an Aura card, reveal it, put it into your hand, then shuffle.

Aven Fleetwing

Flying
Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Somnomancer

When this creature enters, you may tap target creature.

Plains

Deputy of Acquittals

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, you may return another target creature you control to its owner's hand.

Emerge Unscathed

Target creature you control gains protection from the color of your choice until end of turn.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Esper Stormblade

As long as you control another multicolored permanent, this creature gets +1/+1 and has flying.

Turn Aside

Counter target spell that targets a permanent you control.

Ethercaste Knight

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)

Island

Shielding Plax

({G/U} can be paid with either {G} or {U}.)
Enchant creature
When this Aura enters, draw a card.
Enchanted creature can't be the target of spells or abilities your opponents control.

Keep Safe

Counter target spell that targets a permanent you control.
Draw a card.

Bant Sureblade

As long as you control another multicolored permanent, this creature gets +1/+1 and has first strike.

Skyward Spider

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
This creature has flying as long as it's modified. (Equipment, Auras you control, and counters are modifications.)

Hussar Patrol

Flash (You may cast this spell any time you could cast an instant.)
Vigilance

Curiosity

Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Hyena Umbra

Enchant creature
Enchanted creature gets +1/+1 and has first strike.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)