Guttersnipe

Whenever you cast an instant or sorcery spell, Guttersnipe deals 2 damage to each opponent.

Brash Taunter

Indestructible
Whenever Brash Taunter is dealt damage, it deals that much damage to target opponent.
{2}{R}, {T}: Brash Taunter fights another target creature.

Rakdos Locket

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

Bloodfell Caves

Bloodfell Caves enters tapped.
When Bloodfell Caves enters, you gain 1 life.
{T}: Add {B} or {R}.

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Breath of Malfegor

Breath of Malfegor deals 5 damage to each opponent.

Dictate of the Twin Gods

Flash
If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Underworld Dreams

Whenever an opponent draws a card, Underworld Dreams deals 1 damage to that player.

Temple of Malice

Temple of Malice enters tapped.
When Temple of Malice enters, scry 1.
{T}: Add {B} or {R}.

Blazing Volley

Blazing Volley deals 1 damage to each creature your opponents control.

Indulgent Tormentor

Flying
At the beginning of your upkeep, draw a card unless target opponent sacrifices a creature or pays 3 life.

Descent into Avernus

At the beginning of your upkeep, put two descent counters on Descent into Avernus. Then each player creates X Treasure tokens and Descent into Avernus deals X damage to each player, where X is the number of descent counters on Descent into Avernus.

Blisterspit Gremlin

{1}, {T}: Blisterspit Gremlin deals 1 damage to each opponent.
Whenever you cast a noncreature spell, untap Blisterspit Gremlin.

Akoum Refuge

Akoum Refuge enters tapped.
When Akoum Refuge enters, you gain 1 life.
{T}: Add {B} or {R}.

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Kaervek the Merciless

Whenever an opponent casts a spell, Kaervek the Merciless deals damage equal to that spell's mana value to any target.

Prossh, Skyraider of Kher

When you cast this spell, create X 0/1 red Kobold creature tokens named Kobolds of Kher Keep, where X is the amount of mana spent to cast it.
Flying
Sacrifice another creature: Prossh, Skyraider of Kher gets +1/+0 until end of turn.

Arcane Signet

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

Read the Bones

Scry 2, then draw two cards. You lose 2 life. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Smoldering Marsh

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

Command Tower

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Sol Ring

End the Festivities

End the Festivities deals 1 damage to each opponent and each creature and planeswalker they control.