Dragonskull Summit

This land enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Myr Battlesphere

When this creature enters, create four 1/1 colorless Myr artifact creature tokens.
Whenever this creature attacks, you may tap X untapped Myr you control. If you do, this creature gets +X/+0 until end of turn and deals X damage to the player or planeswalker it's attacking.

Crumbling Necropolis

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

Hunted by The Family

Choose up to four target creatures you don't control. For each of them, that creature's controller faces a villainous choice — That creature becomes a 1/1 white Human creature and loses all abilities, or you create a token that's a copy of it.

Combustible Gearhulk

First strike
When this creature enters, target opponent may have you draw three cards. If the player doesn't, you mill three cards, then this creature deals damage to that player equal to the total mana value of those cards.

Sulfur Falls

This land enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Waste Not

Whenever an opponent discards a creature card, create a 2/2 black Zombie creature token.
Whenever an opponent discards a land card, add {B}{B}.
Whenever an opponent discards a noncreature, nonland card, draw a card.

Foundry Inspector

Artifact spells you cast cost {1} less to cast.

Arcane Signet

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Coalstoke Gearhulk

Menace, deathtouch
When this creature enters, put target creature card with mana value 4 or less from a graveyard onto the battlefield under your control with a finality counter on it. That creature gains menace, deathtouch, and haste. At the beginning of your next end step, exile that creature.

The Valeyard

If an opponent would face a villainous choice, they face that choice an additional time. (They can make the same or different choices.)
While voting, you may vote an additional time.

Noxious Gearhulk

Menace
When this creature enters, you may destroy another target creature. If a creature is destroyed this way, you gain life equal to its toughness.

This Is How It Ends

Target creature's owner shuffles it into their library, then faces a villainous choice — They lose 5 life, or they shuffle another creature they own into their library.

Drowned Catacomb

This land enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Counterspell

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Dr. Eggman

Flying
At the beginning of your end step, draw a card. Then each opponent faces a villainous choice — That player discards a card, or you may put a Construct, Robot, or Vehicle card from your hand onto the battlefield.