Drowned Secrets

Whenever you cast a blue spell, target player mills two cards.

Inquisitive Glimmer

Enchantment spells you cast cost {1} less to cast.
Unlock costs you pay cost {1} less.

Island

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.)

Hallowed Fountain

({T}: Add {W} or {U}.)
As Hallowed Fountain enters, you may pay 2 life. If you don't, it enters tapped.

Rest in Peace

When Rest in Peace enters, exile all graveyards.
If a card or token would be put into a graveyard from anywhere, exile it instead.

Tasha's Hideous Laughter

Each opponent exiles cards from the top of their library until that player has exiled cards with total mana value 20 or more.

Dovin's Veto

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

Dance of the Manse

Return up to X target artifact and/or non-Aura enchantment cards each with mana value X or less from your graveyard to the battlefield. If X is 6 or more, those permanents are 4/4 creatures in addition to their other types.

Detention Sphere

When Detention Sphere enters, you may exile target nonland permanent not named Detention Sphere and all other permanents with the same name as that permanent.
When Detention Sphere leaves the battlefield, return the exiled cards to the battlefield under their owner's control.

Omen of the Sea

Flash (You may cast this spell any time you could cast an instant.)
When Omen of the Sea enters, scry 2, then draw a card.
{2}{U}, Sacrifice Omen of the Sea: Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

No More Lies

Counter target spell unless its controller pays {3}. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Sage of Mysteries

Constellation — Whenever an enchantment you control enters, target player mills two cards.

Plains

Patient Rebuilding

At the beginning of your upkeep, target opponent mills three cards, then you draw a card for each land card put into their graveyard this way.

Fraying Sanity

Enchant player
At the beginning of each end step, enchanted player mills X cards, where X is the number of cards put into their graveyard from anywhere this turn.

Farewell

Choose one or more —
• Exile all artifacts.
• Exile all creatures.
• Exile all enchantments.
• Exile all graveyards.

Scrabbling Skullcrab

Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, target player mills two cards. (They put the top two cards of their library into their graveyard.)

Field of Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice Field of Ruin: Destroy target nonbasic land an opponent controls. Each player searches their library for a basic land card, puts it onto the battlefield, then shuffles.

Thirst for Meaning

Draw three cards. Then discard two cards unless you discard an enchantment card.

Teferi's Tutelage

When Teferi's Tutelage enters, draw a card, then discard a card.
Whenever you draw a card, target opponent mills two cards. (They put the top two cards of their library into their graveyard.)