Trickster Mage

{U}, {T}, Discard a card: You may tap or untap target artifact, creature, or land.

Belltower Sphinx

Flying
Whenever a source deals damage to Belltower Sphinx, that source's controller mills that many cards.

Hedron Crab

Landfall — Whenever a land you control enters, target player mills three cards.

Mana Leak

Counter target spell unless its controller pays {3}.

Selhoff Occultist

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

Shriekhorn

Shriekhorn enters with three charge counters on it.
{T}, Remove a charge counter from Shriekhorn: Target player mills two cards.

Merfolk of the Pearl Trident

Fledgling Osprey

Fledgling Osprey has flying as long as it's enchanted.

Island

Snap

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

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Counterspell

Power Sink

Counter target spell unless its controller pays {X}. If that player doesn't, they tap all lands with mana abilities they control and lose all unspent mana.

Curse of the Bloody Tome

Enchant player
At the beginning of enchanted player's upkeep, that player mills two cards.

Tome Scour

Cancel

Elixir of Immortality

{2}, {T}: You gain 5 life. Shuffle Elixir of Immortality and your graveyard into their owner's library.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Dream Twist

Target player mills three cards.
Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)