Ziatora's Proving Ground

({T}: Add {B}, {R}, or {G}.)
This land enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Jund Panorama

{T}: Add {C}.
{1}, {T}, Sacrifice this land: Search your library for a basic Swamp, Mountain, or Forest card, put it onto the battlefield tapped, then shuffle.

Darigaaz's Caldera

When this land enters, sacrifice it unless you return a non-Lair land you control to its owner's hand.
{T}: Add {B}, {R}, or {G}.

Sek'Kuar, Deathkeeper

Whenever another nontoken creature you control dies, create a 3/1 black and red Graveborn creature token with haste.

Geothermal Crevice

This land enters tapped.
{T}: Add {R}.
{T}, Sacrifice this land: Add {B}{G}.

Flameskull

Flying
This creature can't block.
Rejuvenation — When this creature dies, exile it. If you do, exile the top card of your library. Until the end of your next turn, you may play one of those cards. (If you cast Flameskull this way, you can't play the other card, and vice versa.)

Gut, True Soul Zealot

Whenever you attack, you may sacrifice another creature or an artifact. If you do, create a 4/1 black Skeleton creature token with menace that's tapped and attacking. (It can't be blocked except by two or more creatures.)
Choose a Background (You can have a Background as a second commander.)

Golgari Grave-Troll

This creature enters with a +1/+1 counter on it for each creature card in your graveyard.
{1}, Remove a +1/+1 counter from this creature: Regenerate this creature.
Dredge 6 (If you would draw a card, you may mill six cards instead. If you do, return this card from your graveyard to your hand.)

Oversold Cemetery

At the beginning of your upkeep, if you have four or more creature cards in your graveyard, you may return target creature card from your graveyard to your hand.

Unleash the Inferno

Unleash the Inferno deals 7 damage to target creature or planeswalker. When it deals excess damage this way, destroy target artifact or enchantment an opponent controls with mana value less than or equal to that amount of excess damage.

Savage Lands

This land enters tapped.
{T}: Add {B}, {R}, or {G}.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Skeletal Swarming

Each Skeleton you control has trample, attacks each combat if able, and gets +X/+0, where X is the number of other Skeletons you control.
At the beginning of your end step, create a tapped 1/1 black Skeleton creature token. If a creature died this turn, create two of those tokens instead.

Aether Rift

At the beginning of your upkeep, discard a card at random. If you discard a creature card this way, return it from your graveyard to the battlefield unless any player pays 5 life.

Bladewing, Deathless Tyrant

Flying, haste
Whenever Bladewing deals combat damage to a player or planeswalker, for each creature card in your graveyard, create a 2/2 black Zombie Knight creature token with menace.

Skeletonize

Skeletonize deals 3 damage to target creature. When a creature dealt damage this way dies this turn, create a 1/1 black Skeleton creature token with "{B}: Regenerate this token."

Carnage Gladiator

Whenever a creature blocks, that creature's controller loses 1 life.
{1}{B}{R}: Regenerate this creature.

Lightning Skelemental

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

Bone Offering

Create a tapped 4/1 black Skeleton creature token with menace. (Then exile this card. You may cast the artifact later from exile.)

Altar of Bhaal

{2}{B}, {T}, Exile a creature you control: Return target creature card from your graveyard to the battlefield. Activate only as a sorcery.

Altar of Bhaal // Bone Offering

Wake the Dead

Cast this spell only during combat on an opponent's turn.
Return X target creature cards from your graveyard to the battlefield. Sacrifice those creatures at the beginning of the next end step.

Lavalanche

Lavalanche deals X damage to target player or planeswalker and each creature that player or that planeswalker's controller controls.

Rakdos Ringleader

First strike
Whenever this creature deals combat damage to a player, that player discards a card at random.
{B}: Regenerate this creature.