Swamp

Seer of the Last Tomorrow

{U}, {T}, Discard a card: Target player mills three cards.

Psychic Strike

Counter target spell. Its controller mills two cards.

Murder

Island

Mind Rot

Submerged Boneyard

Submerged Boneyard enters tapped.
{T}: Add {U} or {B}.

Tormod's Crypt

{T}, Sacrifice Tormod's Crypt: Exile target player's graveyard.

Dimir Guildgate

This land enters tapped.
{T}: Add {U} or {B}.

Selhoff Occultist

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

Dismal Backwater

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {U} or {B}.

Winds of Rebuke

Return target nonland permanent to its owner's hand. Each player mills two cards.

Thought Collapse

Counter target spell. Its controller mills three cards.

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Ash Barrens

{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Didn't Say Please

Sage's Row Denizen

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

Evolving Wilds

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

Unsummon

Return target creature to its owner's hand.

Venture Deeper

Target player mills four cards. (Then exile this card. You may cast the creature later from exile.)

Merfolk Secretkeeper

Merfolk Secretkeeper // Venture Deeper

Mind Rake

Target player discards two cards.
Overload {1}{B} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Callous Dismissal

Return target nonland permanent to its owner's hand.
Amass Zombies 1. (Put a +1/+1 counter on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)