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.)

Possessed Goat

{3}, Discard a card: Put three +1/+1 counters on Possessed Goat and it becomes a black Demon in addition to its other colors and types. Activate only once.

Mountain

Cracked Skull

Enchant creature
When Cracked Skull enters, look at target player's hand. You may choose a nonland card from it. That player discards that card.
When enchanted creature is dealt damage, destroy it.

Seized from Slumber

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

Cackling Slasher

Deathtouch
Cackling Slasher enters with a +1/+1 counter on it if a creature died this turn.

Murder

Vicious Clown

Whenever another creature you control with power 2 or less enters, Vicious Clown gets +2/+0 until end of turn.

Marvin, Murderous Mimic

Marvin, Murderous Mimic has all activated abilities of creatures you control that don't have the same name as this creature.

Unstoppable Slasher

Deathtouch
Whenever Unstoppable Slasher deals combat damage to a player, they lose half their life, rounded up.
When Unstoppable Slasher dies, if it had no counters on it, return it to the battlefield tapped under its owner's control with two stun counters on it.

Sawblade Skinripper

Menace
{2}, Sacrifice another creature or enchantment: Put a +1/+1 counter on Sawblade Skinripper.
At the beginning of your end step, if you sacrificed one or more permanents this turn, Sawblade Skinripper deals that much damage to any target.

Killer's Mask

When Killer's Mask enters, manifest dread, then attach Killer's Mask to that creature. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)
Equipped creature has menace.
Equip {2}

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Enduring Courage

Whenever another creature you control enters, it gets +2/+0 and gains haste until end of turn.
When Enduring Courage dies, if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)

Plains

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.

Patched Plaything

Double strike
Patched Plaything enters with two -1/-1 counters on it if you cast it from your hand.

Glimmer Seeker

Survival — At the beginning of your second main phase, if Glimmer Seeker is tapped, draw a card if you control a Glimmer creature. If you don't control a Glimmer creature, create a 1/1 white Glimmer enchantment creature token.

Turn Inside Out

Target creature gets +3/+0 until end of turn. When it dies this turn, manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Swamp

Unsettling Twins

When Unsettling Twins enters, manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Fear of the Dark

Whenever Fear of the Dark attacks, if defending player controls no Glimmer creatures, it gains menace and deathtouch until end of turn. (A creature with menace can't be blocked except by two or more creatures.)

Ragged Playmate

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

Neglected Manor

Neglected Manor enters tapped unless a player has 13 or less life.
{T}: Add {W} or {B}.

The Wandering Rescuer

Flash
Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Double strike
Other tapped creatures you control have hexproof.

Cult Healer

Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, Cult Healer gains lifelink until end of turn.

Conductive Machete

When Conductive Machete enters, manifest dread, then attach Conductive Machete to that creature. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)
Equipped creature gets +2/+1.
Equip {4}

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.