Mind Rot

Clone

You may have Clone enter as a copy of any creature on the battlefield.

Black Cat

When Black Cat dies, target opponent discards a card at random.

Drowned Catacomb

Drowned Catacomb enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Smallpox

Each player loses 1 life, discards a card, sacrifices a creature of their choice, then sacrifices a land of their choice.

Curse of the Bloody Tome

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

Rotting Rats

When Rotting Rats enters, each player discards a card.
Unearth {1}{B} ({1}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Cut Your Losses

Casualty 2 (As you cast this spell, you may sacrifice a creature with power 2 or greater. When you do, copy this spell and you may choose a new target for the copy.)
Target player mills half their library, rounded down.

Rise from the Grave

Put target creature card from a graveyard onto the battlefield under your control. That creature is a black Zombie in addition to its other colors and types.

Island

Ob Nixilis, the Fallen

Landfall — Whenever a land you control enters, you may have target player lose 3 life. If you do, put three +1/+1 counters on Ob Nixilis, the Fallen.

Scepter of Fugue

{1}{B}, {T}: Target player discards a card. Activate only during your turn.

Telemin Performance

Target opponent reveals cards from the top of their library until they reveal a creature card. That player puts all noncreature cards revealed this way into their graveyard, then you put the creature card onto the battlefield under your control.

Mind Control

Enchant creature
You control enchanted creature.

Sage's Row Denizen

Whenever another blue creature you control enters, target player mills two cards.

Corrupt Court Official

When Corrupt Court Official enters, target opponent discards a card.

Changeling Outcast

Changeling (This card is every creature type.)
Changeling Outcast can't block and can't be blocked.

Ravenous Rats

When Ravenous Rats enters, target opponent discards a card.

Cathartic Adept

Salt Marsh

Salt Marsh enters tapped.
{T}: Add {U} or {B}.

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Vapor Snag

Return target creature to its owner's hand. Its controller loses 1 life.

Djinn of Wishes

Flying
Djinn of Wishes enters with three wish counters on it.
{2}{U}{U}, Remove a wish counter from Djinn of Wishes: Reveal the top card of your library. You may play that card without paying its mana cost. If you don't, exile it.

Swamp

Duskmantle Guildmage

{1}{U}{B}: Whenever a card is put into an opponent's graveyard from anywhere this turn, that player loses 1 life.
{2}{U}{B}: Target player mills two cards.

Liliana Vess

+1: Target player discards a card.
−2: Search your library for a card, then shuffle and put that card on top.
−8: Put all creature cards from all graveyards onto the battlefield under your control.

Jace's Mindseeker

Flying
When Jace's Mindseeker enters, target opponent mills five cards. You may cast an instant or sorcery spell from among them without paying its mana cost.

Rotcrown Ghoul

When Rotcrown Ghoul dies, target player mills five cards.

Shriekgeist

Flying
Whenever Shriekgeist deals combat damage to a player, that player mills two cards.

Unsummon

Return target creature to its owner's hand.

Megrim

Whenever an opponent discards a card, Megrim deals 2 damage to that player.

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.)