Helm of Obedience

, : Target opponent mills a card, then repeats this process until a creature card or X cards have been put into their graveyard this way, whichever comes first. If one or more creature cards were put into that graveyard this way, sacrifice Helm of Obedience and put one of them onto the battlefield under your control. X can’t be 0.

Deep Spawn

Trample
At the beginning of your upkeep, sacrifice Deep Spawn unless you mill two cards.
: Deep Spawn gains shroud until end of turn and doesn’t untap during your next untap step. Tap Deep Spawn. (A creature with shroud can’t be the target of spells or abilities.)

Sanity Grinding

Chroma — Reveal the top ten cards of your library. For each blue mana symbol in the mana costs of the revealed cards, target opponent mills a card. Then put the cards you revealed this way on the bottom of your library in any order.

Drowner Initiate

Whenever a player casts a blue spell, you may pay . If you do, target player mills two cards.

Memory Sluice

Target player mills four cards.
Conspire (As you cast this spell, you may tap two untapped creatures you control that share a color with it. When you do, copy it and you may choose a new target for the copy.)

Ink Dissolver

Kinship — At the beginning of your upkeep, you may look at the top card of your library. If it shares a creature type with Ink Dissolver, you may reveal it. If you do, each opponent mills three cards.

Merrow Witsniper

When Merrow Witsniper enters the battlefield, target player mills a card.

Broken Ambitions

Counter target spell unless its controller pays . Clash with an opponent. If you win, that spell’s controller mills four cards. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher converted mana cost.)

Lammastide Weave

Choose a card name, then target player mills a card. If a card with the chosen name was milled this way, you gain life equal to its converted mana cost.
Draw a card.

Jace Beleren

+2: Each player draws a card.
−1: Target player draws a card.
−10: Target player mills twenty cards.

Chains of Mephistopheles

If a player would draw a card except the first one they draw in each of their draw steps, that player discards a card instead. If the player discards a card this way, they draw a card. If the player doesn’t discard a card this way, they mill a card.

Dreamborn Muse

At the beginning of each player’s upkeep, that player mills X cards, where X is the number of cards in their hand.

Traumatize

Target player mills half their library, rounded down.

Millstone

, : Target player mills two cards.

Dakmor Salvage

Dakmor Salvage enters the battlefield tapped.
: Add .
Dredge 2 (If you would draw a card, you may mill two cards instead. If you do, return this card from your graveyard to your hand.)

Whetwheel

, : Target player mills X cards.
Morph (You may cast this card face down as a 2/2 creature for . Turn it face up any time for its morph cost.)

Enigma Eidolon

, Sacrifice Enigma Eidolon: Target player mills three cards.
Whenever you cast a multicolored spell, you may return Enigma Eidolon from your graveyard to your hand.

Golgari Thug

When Golgari Thug dies, put target creature card from your graveyard on top of your library.
Dredge 4 (If you would draw a card, you may mill four cards instead. If you do, return this card from your graveyard to your hand.)

Necroplasm

At the beginning of your upkeep, put a +1/+1 counter on Necroplasm.
At the beginning of your end step, destroy each creature with converted mana cost equal to the number of +1/+1 counters on Necroplasm.
Dredge 2 (If you would draw a card, you may mill two cards instead. If you do, return this card from your graveyard to your hand.)

Golgari Grave-Troll

Golgari Grave-Troll enters the battlefield with a +1/+1 counter on it for each creature card in your graveyard.
, Remove a +1/+1 counter from Golgari Grave-Troll: Regenerate Golgari Grave-Troll.
Dredge 6 (If you would draw a card, you may mill six cards instead. If you do, return this card from your graveyard to your hand.)