Chart a Course

Draw two cards. Then discard a card unless you attacked this turn.

Drowned Secrets

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

Didn't Say Please

Counter target spell. Its controller mills three cards.

Divination

Ashiok, Dream Render

Spells and abilities your opponents control can't cause their controller to search their library.
−1: Target player mills four cards. Then exile each opponent's graveyard.

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.

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.

Wall of Lost Thoughts

Defender (This creature can't attack.)
When Wall of Lost Thoughts enters, target player mills four cards. (They put the top four cards of their library into their graveyard.)

Maddening Cacophony

Kicker {3}{U}
Each opponent mills eight cards. If this spell was kicked, instead each opponent mills half their library, rounded up.

Tome Scour

Island

Traumatize

Target player mills half their library, rounded down.

Venture Deeper

Target player mills four cards. (Then exile this card. You may cast the creature later from exile.)