Spawn of Rix Maadi

Unleash (You may have this creature enter the battlefield with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)

Deviant Glee

Enchant creature
Enchanted creature gets +2/+1 and has "{R}: This creature gains trample until end of turn."

Riot Spikes

({B/R} can be paid with either {B} or {R}.)
Enchant creature
Enchanted creature gets +2/-1.

Cryptborn Horror

Trample
Cryptborn Horror enters the battlefield with X +1/+1 counters on it, where X is the total life lost by your opponents this turn.

Morgue Burst

Return target creature card from your graveyard to your hand. Morgue Burst deals damage to any target equal to the power of the card returned this way.

Rakdos Ickspitter

{T}: Rakdos Ickspitter deals 1 damage to target creature and that creature's controller loses 1 life.

Blazing Specter

Flying, haste
Whenever Blazing Specter deals combat damage to a player, that player discards a card.

Fists of the Demigod

Enchant creature
As long as enchanted creature is black, it gets +1/+1 and has wither. (It deals damage to creatures in the form of -1/-1 counters.)
As long as enchanted creature is red, it gets +1/+1 and has first strike.

Carnival Hellsteed

First strike, haste
Unleash (You may have this creature enter the battlefield with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)

Rakdos, Lord of Riots

You can't cast this spell unless an opponent lost life this turn.
Flying, trample
Creature spells you cast cost {1} less to cast for each 1 life your opponents have lost this turn.

Thrill-Kill Assassin

Deathtouch
Unleash (You may have this creature enter the battlefield with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)

Swamp

Mountain

Rakdos Shred-Freak

Rakdos Ragemutt

Rakdos's Return

Rakdos's Return deals X damage to target opponent or planeswalker. That player or that planeswalker's controller discards X cards.

Havoc Festival

Players can't gain life.
At the beginning of each player's upkeep, that player loses half their life, rounded up.

Impetuous Devils

Trample, haste
When Impetuous Devils attacks, up to one target creature defending player controls blocks it this combat if able.
At the beginning of the end step, sacrifice Impetuous Devils.

Splatter Thug

First strike
Unleash (You may have this creature enter the battlefield with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)