Negate

Arms of Hadar

Creatures target player controls get -2/-2 until end of turn.

Radiant Fountain

When this land enters, you gain 2 life.
{T}: Add {C}.

Contentious Plan

Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Draw a card.

Peat Bog

This land enters tapped with two depletion counters on it.
{T}, Remove a depletion counter from this land: Add {B}{B}. If there are no depletion counters on this land, sacrifice it.

Diabolic Edict

Target player sacrifices a creature of their choice.

Bring the Ending

Counter target spell unless its controller pays {2}.
Corrupted — Counter that spell instead if its controller has three or more poison counters.

Probe

Kicker {1}{B} (You may pay an additional {1}{B} as you cast this spell.)
Draw three cards, then discard two cards. If this spell was kicked, target player discards two cards.

Dimir Aqueduct

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {U}{B}.

Prologue to Phyresis

Each opponent gets a poison counter.
Draw a card.

Infectious Inquiry

You draw two cards and you lose 2 life. Each opponent gets a poison counter.

Experimental Augury

Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Maestros Theater

When this land enters, sacrifice it. When you do, search your library for a basic Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Saprazzan Skerry

This land enters tapped with two depletion counters on it.
{T}, Remove a depletion counter from this land: Add {U}{U}. If there are no depletion counters on this land, sacrifice it.

Crypt Incursion

Exile all creature cards from target player's graveyard. You gain 3 life for each card exiled this way.

Island

Cast Down

Vraska's Fall

Each opponent sacrifices a creature or planeswalker of their choice and gets a poison counter.

Bojuka Bog

This land enters tapped.
When this land enters, exile target player's graveyard.
{T}: Add {B}.

Suffocating Fumes

Creatures your opponents control get -1/-1 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Blue Elemental Blast

Choose one —
• Counter target red spell.
• Destroy target red permanent.

Swamp

Mystical Teachings

Search your library for an instant card or a card with flash, reveal it, put it into your hand, then shuffle.
Flashback {5}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Hydroblast

Choose one —
• Counter target spell if it's red.
• Destroy target permanent if it's red.

Dismal Backwater

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

Serrated Arrows

This artifact enters with three arrowhead counters on it.
At the beginning of your upkeep, if there are no arrowhead counters on this artifact, sacrifice it.
{T}, Remove an arrowhead counter from this artifact: Put a -1/-1 counter on target creature.