Most Valuable Slayer

Whenever you attack, target attacking creature gets +1/+0 and gains first strike until end of turn.

Jump Scare

Until end of turn, target creature gets +2/+2, gains flying, and becomes a Horror enchantment creature in addition to its other types.

Veteran Survivor

Survival — At the beginning of your second main phase, if Veteran Survivor is tapped, exile up to one target card from a graveyard.
As long as there are three or more cards exiled with Veteran Survivor, it gets +3/+3 and has hexproof. (It can't be the target of spells or abilities your opponents control.)

Hand That Feeds

Delirium — Whenever Hand That Feeds attacks while there are four or more card types among cards in your graveyard, it gets +2/+0 and gains menace until end of turn. (It can't be blocked except by two or more creatures.)

Elegant Rotunda

(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.)
When you unlock this door, put a +1/+1 counter on each of up to two target creatures.

Grand Entryway

(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.)
When you unlock this door, create a 1/1 white Glimmer enchantment creature token.

Grand Entryway // Elegant Rotunda

Arabella, Abandoned Doll

Whenever Arabella, Abandoned Doll attacks, it deals X damage to each opponent and you gain X life, where X is the number of creatures you control with power 2 or less.

Clockwork Percussionist

Haste
When Clockwork Percussionist dies, exile the top card of your library. You may play it until the end of your next turn.

Raucous Carnival

Raucous Carnival enters tapped unless a player has 13 or less life.
{T}: Add {R} or {W}.

Shepherding Spirits

Flying
Plainscycling {2} ({2}, Discard this card: Search your library for a Plains card, reveal it, put it into your hand, then shuffle.)

Grab the Prize

As an additional cost to cast this spell, discard a card.
Draw two cards. If the discarded card wasn't a land card, Grab the Prize deals 2 damage to each opponent.

Friendly Ghost

Flying
When Friendly Ghost enters, target creature gets +2/+4 until end of turn.

Rampaging Soulrager

Rampaging Soulrager gets +3/+0 as long as there are two or more unlocked doors among Rooms you control.

Infernal Phantom

Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, Infernal Phantom gets +2/+0 until end of turn.
When Infernal Phantom dies, it deals damage equal to its power to any target.

Hardened Escort

Whenever Hardened Escort attacks, another target creature you control gets +1/+0 and gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Seized from Slumber

This spell costs {3} less to cast if it targets a tapped creature.
Destroy target creature.

Plains

Keys to the House

{1}, {T}, Sacrifice Keys to the House: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
{3}, {T}, Sacrifice Keys to the House: Lock or unlock a door of target Room you control. Activate only as a sorcery.

Living Phone

When Living Phone dies, look at the top five cards of your library. You may reveal a creature card with power 2 or less from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Midnight Mayhem

Create three 1/1 red Gremlin creature tokens. Gremlins you control gain menace, lifelink, and haste until end of turn. (A creature with menace can't be blocked except by two or more creatures.)

Attack-in-the-Box

Whenever Attack-in-the-Box attacks, you may have it get +4/+0 until end of turn. If you do, sacrifice it at the beginning of the next end step.

Fear of Surveillance

Vigilance
Whenever Fear of Surveillance attacks, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Untimely Malfunction

Choose one —
• Destroy target artifact.
• Change the target of target spell or ability with a single target.
• One or two target creatures can't block this turn.

Scorching Dragonfire

Scorching Dragonfire deals 3 damage to target creature or planeswalker. If that creature or planeswalker would die this turn, exile it instead.

Ragged Playmate

{1}, {T}: Target creature with power 2 or less can't be blocked this turn.

Razorkin Needlehead

Razorkin Needlehead has first strike during your turn.
Whenever an opponent draws a card, Razorkin Needlehead deals 1 damage to them.