Aven Mindcensor

Flash
Flying
If an opponent would search a library, that player searches the top four cards of that library instead.

Dovin's Veto

This spell can't be countered.
Counter target noncreature spell.

Verity Circle

Whenever a creature an opponent controls becomes tapped, if it isn't being declared as an attacker, you may draw a card.
{4}{U}: Tap target creature without flying.

Toski, Bearer of Secrets

This spell can't be countered.
Indestructible
Toski, Bearer of Secrets attacks each combat if able.
Whenever a creature you control deals combat damage to a player, draw a card.

Grand Arbiter Augustin IV

White spells you cast cost {1} less to cast.
Blue spells you cast cost {1} less to cast.
Spells your opponents cast cost {1} more to cast.

Swift Spiral

Exile target nontoken creature. Return it to the battlefield under its owner's control at the beginning of the next end step.

Twining Twins

Twining Twins // Swift Spiral

Watcher of the Spheres

Flying
Creature spells with flying you cast cost {1} less to cast.
Whenever another creature with flying enters the battlefield under your control, Watcher of the Spheres gets +1/+1 until end of turn.

Faerie Mastermind

Flash
Flying
Whenever an opponent draws their second card each turn, you draw a card.
{3}{U}: Each player draws a card.

Judge's Familiar

Flying
Sacrifice Judge's Familiar: Counter target instant or sorcery spell unless its controller pays {1}.

Birds of Paradise

Bloom Tender

{T}: For each color among permanents you control, add one mana of that color.

Counterspell

Hylda of the Icy Crown

Whenever you tap an untapped creature an opponent controls, you may pay {1}. When you do, choose one —
• Create a 4/4 white and blue Elemental creature token.
• Put a +1/+1 counter on each creature you control.
• Scry 2, then draw a card.

Llanowar Elves

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Derevi, Empyrial Tactician

Flying
Whenever Derevi, Empyrial Tactician enters the battlefield or a creature you control deals combat damage to a player, you may tap or untap target permanent.
{1}{G}{W}{U}: Put Derevi onto the battlefield from the command zone.