Selhoff Occultist

Whenever Selhoff Occultist or another creature dies, target player mills a card.

Memory Erosion

Whenever an opponent casts a spell, that player mills two cards.

Ambassador Laquatus

Sphinx's Tutelage

Whenever you draw a card, target opponent mills two cards. If two nonland cards that share a color were milled this way, repeat this process.
{5}{U}: Draw a card, then discard a card.

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.

Traumatize

Target player mills half their library, rounded down.

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.)

Thought Collapse

Counter target spell. Its controller mills three cards.

Bruvac the Grandiloquent

If an opponent would mill one or more cards, they mill twice that many cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

Psychic Corrosion

Whenever you draw a card, each opponent mills two cards.

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.

Drowned Secrets

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

Thought Scour

Target player mills two cards.
Draw a card.

Fleet Swallower

Whenever Fleet Swallower attacks, target player mills half their library, rounded up.