Hypersonic Dragon

Flying, haste
You may cast sorcery spells as though they had flash. (You may cast them any time you could cast an instant.)

Watery Grave

({T}: Add {U} or {B}.)
As Watery Grave enters, you may pay 2 life. If you don't, it enters tapped.

Secret Passage

Secret Passage enters tapped.
{T}: Add {U} or {B}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Footlight Fiend

When Footlight Fiend dies, it deals 1 damage to any target.

Izzet Boilerworks

Izzet Boilerworks enters tapped.
When Izzet Boilerworks enters, return a land you control to its owner's hand.
{T}: Add {U}{R}.

Library

Library enters tapped.
{T}: Add {U} or {R}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Spawn of Mayhem

Spectacle {1}{B}{B} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Flying, trample
At the beginning of your upkeep, Spawn of Mayhem deals 1 damage to each player. Then if you have 10 or less life, put a +1/+1 counter on Spawn of Mayhem.

Thriving Moor

Thriving Moor enters tapped. As it enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Dimir Aqueduct

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

Havoc Jester

Whenever you sacrifice a permanent, Havoc Jester deals 1 damage to any target.

Blood Crypt

({T}: Add {B} or {R}.)
As Blood Crypt enters, you may pay 2 life. If you don't, it enters tapped.

Mountain

Frenzied Gorespawn

When Frenzied Gorespawn enters, for each opponent, goad target creature that player controls. (Until your next turn, those creatures attack each combat if able and attack a player other than you if able.)
Whenever one or more creatures attack one of your opponents, those creatures gain menace until end of turn.

Thriving Bluff

Thriving Bluff enters tapped. As it enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

Carnage Interpreter

When Carnage Interpreter enters, discard your hand, then investigate four times. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
As long as you have one or fewer cards in hand, Carnage Interpreter gets +2/+2 and has menace.

Steam Vents

({T}: Add {U} or {R}.)
As Steam Vents enters, you may pay 2 life. If you don't, it enters tapped.

Rakdos Carnarium

Rakdos Carnarium enters tapped.
When Rakdos Carnarium enters, return a land you control to its owner's hand.
{T}: Add {B}{R}.

Rakdos, the Showstopper

Flying, trample
When Rakdos, the Showstopper enters, flip a coin for each creature that isn't a Demon, Devil, or Imp. Destroy each creature whose coin comes up tails.

Swamp

Billiard Room

Billiard Room enters tapped.
{T}: Add {B} or {R}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Dimir Strandcatcher

Flying
Whenever you attack, surveil X, where X is the number of opponents being attacked.
At the beginning of each end step, if three or more cards were put into your graveyard from anywhere other than the battlefield this turn, draw a card.