Jace's Erasure

Whenever you draw a card, you may have target player mill a card.

Serum Visions

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.)

Doorkeeper

Defender
{2}{U}, {T}: Target player mills X cards, where X is the number of creatures you control with defender.

Drowned Secrets

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

Thought Scour

Target player mills two cards.
Draw a card.

Island

Coral Colony

Defender
{1}{U}, {T}: Target player mills X cards, where X is the number of creatures you control with defender. (To mill a card, a player puts the top card of their library into their graveyard.)

Snap

Return target creature to its owner's hand. Untap up to two lands.

Didn't Say Please

Counter target spell. Its controller mills three cards.

Overwhelmed Apprentice

When Overwhelmed Apprentice enters, each opponent mills two cards. Then you 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.)