Counterspell

Dimir Aqueduct

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

Snow-Covered Island

Hydroblast

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

Anoint with Affliction

Exile target creature if it has mana value 3 or less.
Corrupted — Exile that creature instead if its controller has three or more poison counters.

Mutagenic Growth

({G/P} can be paid with either {G} or 2 life.)
Target creature gets +2/+2 until end of turn.

Prologue to Phyresis

Each opponent gets a poison counter.
Draw a card.

Plague Stinger

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Cracked Skull

Enchant creature
When Cracked Skull enters, look at target player's hand. You may choose a nonland card from it. That player discards that card.
When enchanted creature is dealt damage, destroy it.

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.

Cast Down

Disfigure

Target creature gets -2/-2 until end of turn.

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.)

Ichorclaw Myr

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Whenever Ichorclaw Myr becomes blocked, it gets +2/+2 until end of turn.

Thrummingbird

Flying
Whenever Thrummingbird deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Snow-Covered Swamp

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Mana Leak

Counter target spell unless its controller pays {3}.

Dimir Guildgate

Dimir Guildgate enters tapped.
{T}: Add {U} or {B}.

Blighted Agent

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Blighted Agent can't be blocked.

Unearth

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

Duress

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

Relic's Roar

Until end of turn, target artifact or creature becomes a Dinosaur artifact creature with base power and toughness 4/3 in addition to its other types.

Give In to Violence

Target creature gets +2/+2 and gains lifelink until end of turn.

Whisper of the Dross

Target creature gets -1/-1 until end of turn. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)