Fear of Sleep Paralysis

Flying
Eerie — Whenever Fear of Sleep Paralysis or another enchantment you control enters and whenever you fully unlock a Room, tap up to one target creature and put a stun counter on it.
Stun counters can't be removed from permanents your opponents control. (They won't untap if they have stun counters.)

Crippling Fear

Choose a creature type. Creatures that aren't of the chosen type get -3/-3 until end of turn.

Worst Fears

You control target player during that player's next turn. Exile Worst Fears. (You see all cards that player could see and make all decisions for the player.)

Fear

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature has fear. (It can't be blocked except by artifact creatures and/or black creatures.)

Fear of Death

Enchant creature
When Fear of Death enters, mill two cards. (Put the top two cards of your library into your graveyard.)
Enchanted creature gets -X/-0, where X is the number of cards in your graveyard.

Fear of Isolation

As an additional cost to cast this spell, return a permanent you control to its owner's hand.
Flying

Fear of Failed Tests

Whenever Fear of Failed Tests deals combat damage to a player, draw that many cards.

Umbris, Fear Manifest

Umbris, Fear Manifest gets +1/+1 for each card your opponents own in exile.
Whenever Umbris or another Nightmare or Horror you control enters, target opponent exiles cards from the top of their library until they exile a land 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.)

Fear of Lost Teeth

When Fear of Lost Teeth dies, it deals 1 damage to any target and you gain 1 life.

Fear of Infinity

Flying, lifelink
Fear of Infinity can't block.
Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, you may return Fear of Infinity from your graveyard to your hand.

Triskaidekaphobia

At the beginning of your upkeep, choose one —
• Each player with exactly 13 life loses the game, then each player gains 1 life.
• Each player with exactly 13 life loses the game, then each player loses 1 life.

Fear of Falling

Flying
Whenever Fear of Falling attacks, target creature defending player controls gets -2/-0 and loses flying until your next turn.

Claustrophobia

Enchant creature
When Claustrophobia enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Mortiphobia

{1}{B}, Discard a card: Exile target card from a graveyard.
{1}{B}, Sacrifice Mortiphobia: Exile target card from a graveyard.

Fear of Impostors

Flash
When Fear of Impostors enters, counter target spell. Its controller manifests dread. (That player looks at the top two cards of their library, then puts one onto the battlefield face down as a 2/2 creature and the other into their graveyard. If it's a creature card, it can be turned face up any time for its mana cost.)

Ashiok, Sculptor of Fears

+2: Draw a card. Each player mills two cards.
−5: Put target creature card from a graveyard onto the battlefield under your control.
−11: Gain control of all creatures target opponent controls.

Agoraphobia

Enchant creature
Enchanted creature gets -5/-0.
{2}{U}: Return Agoraphobia to its owner's hand.