Smoldering Marsh

({T}: Add {B} or {R}.)
Smoldering Marsh enters tapped unless you control two or more basic lands.

Kathari Bomber

Flying
When Kathari Bomber deals combat damage to a player, create two 1/1 red Goblin creature tokens and sacrifice Kathari Bomber.
Unearth {3}{B}{R} ({3}{B}{R}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Foreboding Ruins

As Foreboding Ruins enters, you may reveal a Swamp or Mountain card from your hand. If you don't, Foreboding Ruins enters tapped.
{T}: Add {B} or {R}.

Obosh, the Preypiercer

Companion — Your starting deck contains only cards with odd mana values and land cards. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
If a source you control with an odd mana value would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Judith, the Scourge Diva

Other creatures you control get +1/+0.
Whenever a nontoken creature you control dies, Judith, the Scourge Diva deals 1 damage to any target.

Kill-Suit Cultist

Kill-Suit Cultist attacks each combat if able.
{B}, Sacrifice Kill-Suit Cultist: The next time damage would be dealt to target creature this turn, destroy that creature instead.

Lyzolda, the Blood Witch

{2}, Sacrifice a creature: Lyzolda, the Blood Witch deals 2 damage to any target if the sacrificed creature was red. Draw a card if the sacrificed creature was black.

Manaforge Cinder

{1}: Add {B} or {R}. Activate no more than three times each turn.

Mountain

Hellhole Flailer

Unleash (You may have this creature enter with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)
{2}{B}{R}, Sacrifice Hellhole Flailer: Hellhole Flailer deals damage equal to its power to target player or planeswalker.

Blood Cultist

{T}: Blood Cultist deals 1 damage to target creature.
Whenever a creature dealt damage by Blood Cultist this turn dies, put a +1/+1 counter on Blood Cultist.

Swamp

Lightning Skelemental

Trample, haste
Whenever Lightning Skelemental deals combat damage to a player, that player discards two cards.
At the beginning of the end step, sacrifice Lightning Skelemental.

Rakdos Locket

{T}: Add {B} or {R}.
{B/R}{B/R}{B/R}{B/R}, {T}, Sacrifice Rakdos Locket: Draw two cards.

Immersturm Skullcairn

Immersturm Skullcairn enters tapped.
{T}: Add {B}.
{1}{B}{R}{R}, {T}, Sacrifice Immersturm Skullcairn: It deals 3 damage to target player. That player discards a card. Activate only as a sorcery.

Blightning

Blightning deals 3 damage to target player or planeswalker. That player or that planeswalker's controller discards two cards.