Stern Dismissal

Return target creature or enchantment an opponent controls to its owner's hand.

Annul

Counter target artifact or enchantment spell.

Erratic Apparition

Flying, vigilance
Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, Erratic Apparition gets +1/+1 until end of turn.

Ice Out

Bargain (You may sacrifice an artifact, enchantment, or token as you cast this spell.)
This spell costs {1} less to cast if it's bargained.
Counter target spell.

Locker Room

Whenever one or more creatures you control deal combat damage to a player, draw a card.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Bottomless Pool

When you unlock this door, return up to one target creature to its owner's hand.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Bottomless Pool // Locker Room

Unwind

Counter target noncreature spell. Untap up to three lands.

Callous Dismissal

Return target nonland permanent to its owner's hand.
Amass Zombies 1. (Put a +1/+1 counter on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)

Tolarian Terror

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)

Counterspell

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Brine Giant

This spell costs {1} less to cast for each enchantment you control.

Negate

Drake Familiar

Flying
When Drake Familiar enters, sacrifice it unless you return an enchantment to its owner's hand.

Cryptic Serpent

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.

Creeping Peeper

{T}: Add {U}. Spend this mana only to cast an enchantment spell, unlock a door, or turn a permanent face up.

Blink of an Eye

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
Return target nonland permanent to its owner's hand. If this spell was kicked, draw a card.