Enemy of Enlightenment

Flying
Enemy of Enlightenment gets -1/-1 for each card in your opponents' hands.
At the beginning of your upkeep, each player discards a card.

Flamespeaker's Will

Enchant creature you control
Enchanted creature gets +1/+1.
Whenever enchanted creature deals combat damage to a player, you may sacrifice Flamespeaker's Will. If you do, destroy target artifact.

Stonespeaker Crystal

{T}: Add {C}{C}.
{2}, {T}, Sacrifice Stonespeaker Crystal: Exile any number of target players' graveyards. Draw a card.

Warehouse Thief

{2}, {T}, Sacrifice an artifact or creature: Exile the top card of your library. Until the end of your next turn, you may play that card.

Mayhem Devil

Whenever a player sacrifices a permanent, Mayhem Devil deals 1 damage to any target.

Smoldering Marsh

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

Archetype of Finality

Creatures you control have deathtouch.
Creatures your opponents control lose deathtouch and can't have or gain deathtouch.

Desecration Demon

Flying
At the beginning of each combat, any opponent may sacrifice a creature. If a player does, tap Desecration Demon and put a +1/+1 counter on it.

Cadaver Imp

Flying
When Cadaver Imp enters the battlefield, you may return target creature card from your graveyard to your hand.

Battle-Rage Blessing

Target creature gains deathtouch and indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Gruesome Deformity

Enchant creature
Enchanted creature has intimidate. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Indulgent Tormentor

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

Tyrannical Pitlord

Flying, trample
As Tyrannical Pitlord enters the battlefield, choose another creature you control.
The chosen creature gets +3/+3 and has flying.
When Tyrannical Pitlord leaves the battlefield, sacrifice the chosen creature.

Polluted Bonds

Whenever a land enters the battlefield under an opponent's control, that player loses 2 life and you gain 2 life.

Unholy Indenture

Enchant creature
When enchanted creature dies, return that card to the battlefield under your control with a +1/+1 counter on it.

Vrock

Flying
Toxic Spores — At the beginning of your end step, if a permanent you controlled left the battlefield this turn, each opponent loses 3 life.

Charcoal Diamond

Charcoal Diamond enters the battlefield tapped.
{T}: Add {B}.

Inherited Fiend

Flying
{2}{B}: Exile target creature card from a graveyard. Put a +1/+1 counter on Inherited Fiend.

Heirloom Mirror

{1}, {T}, Pay 1 life, Discard a card: Draw a card, mill a card, then put a ritual counter on Heirloom Mirror. Then if it has three or more ritual counters on it, remove them and transform it. Activate only as a sorcery.

Heirloom Mirror // Inherited Fiend

Karlach, Fury of Avernus

Whenever you attack, if it's the first combat phase of the turn, untap all attacking creatures. They gain first strike until end of turn. After this phase, there is an additional combat phase.
Choose a Background (You can have a Background as a second commander.)

Cut of the Profits

Casualty 3 (As you cast this spell, you may sacrifice a creature with power 3 or greater. When you do, copy this spell.)
You draw X cards and you lose X life.

Soulflayer

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
If a creature card with flying was exiled with Soulflayer's delve ability, Soulflayer has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, reach, trample, and vigilance.

Hobblefiend

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
{1}, Sacrifice another creature: Put a +1/+1 counter on Hobblefiend.

Archdemon of Greed

Flying, trample
At the beginning of your upkeep, sacrifice a Human. If you can't, tap Archdemon of Greed and it deals 9 damage to you.

Ravenous Demon

Sacrifice a Human: Transform Ravenous Demon. Activate only as a sorcery.

Ravenous Demon // Archdemon of Greed

Bedevil

Destroy target artifact, creature, or planeswalker.

Getaway Car

Haste
Whenever Getaway Car attacks or blocks, return up to one target creature that crewed it this turn to its owner's hand.
Crew 1

Rose Room Treasurer

Alliance — Whenever another creature enters the battlefield under your control, create a Treasure token if this is the first or second time this ability has resolved this turn. Otherwise, you may pay {X}. When you do, Rose Room Treasurer deals X damage to any target.

Corpse Explosion

As an additional cost to cast this spell, exile a creature card from your graveyard.
Corpse Explosion deals damage equal to the exiled card's power to each creature and each planeswalker.

Mountain

Oni of Wild Places

Haste
At the beginning of your upkeep, return a red creature you control to its owner's hand.

Rakdos Cackler

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.)

Chaos Imps

Flying
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.)
Chaos Imps has trample as long as it has a +1/+1 counter on it.

Mahadi, Emporium Master

At the beginning of your end step, create a Treasure token for each creature that died this turn. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Undercity Plague

Target player loses 1 life, discards a card, then sacrifices a permanent.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Chandra, Bold Pyromancer

+1: Add {R}{R}. Chandra, Bold Pyromancer deals 2 damage to target player.
−3: Chandra, Bold Pyromancer deals 3 damage to target creature or planeswalker.
−7: Chandra, Bold Pyromancer deals 10 damage to target player and each creature and planeswalker they control.

Foreboding Ruins

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

Sin Prodder

Menace
At the beginning of your upkeep, reveal the top card of your library. Any opponent may have you put that card into your graveyard. If a player does, Sin Prodder deals damage to that player equal to that card's mana value. Otherwise, put that card into your hand.

Fetid Imp

Flying
{B}: Fetid Imp gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)

Festival Crasher

Whenever you cast an instant or sorcery spell, Festival Crasher gets +2/+0 until end of turn.

Dark Banishing

Destroy target nonblack creature. It can't be regenerated.

Mayhem Patrol

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Mayhem Patrol attacks, target creature gets +1/+0 until end of turn.
Blitz {1}{R} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Volcanic Strength

Enchant creature
Enchanted creature gets +2/+2 and has mountainwalk. (It can't be blocked as long as defending player controls a Mountain.)

Hulking Devil

Awoken Demon

Ecstatic Awakener

{2}{B}, Sacrifice another creature: Draw a card, then transform Ecstatic Awakener. Activate only once each turn.

Ecstatic Awakener // Awoken Demon

Rakdos Signet

Havoc Jester

Whenever you sacrifice a permanent, Havoc Jester deals 1 damage to any target.

Rakdos Headliner

Haste
Echo—Discard a card. (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)

Hellrider

Haste
Whenever a creature you control attacks, Hellrider deals 1 damage to the player or planeswalker it's attacking.

In Thrall to the Pit

Kicker {2}{B} (You may pay an additional {2}{B} as you cast this spell.)
Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. If this spell was kicked, sacrifice that creature at the beginning of the next end step.

Temple of Malice

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

Valor Singer

Combat Inspiration — At the beginning of combat on your turn, target creature you control gets +1/+0 until end of turn.

Simian Spirit Guide

Exile Simian Spirit Guide from your hand: Add {R}.

Nefarious Imp

Flying
Whenever one or more permanents you control leave the battlefield, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Palladium Myr

Thraxodemon

{3}, {T}, Sacrifice another creature or artifact: Draw a card.

Raphael, Fiendish Savior

Flying
Other Demons, Devils, Imps, and Tieflings you control get +1/+1 and have lifelink.
At the beginning of each end step, if a creature card was put into your graveyard from anywhere this turn, create a 1/1 red Devil creature token with "When this creature dies, it deals 1 damage to any target."

Swamp

Guildsworn Prowler

Deathtouch
When Guildsworn Prowler dies, if it wasn't blocking, draw a card.

Chain Devil

Animate Chains — When Chain Devil enters the battlefield, each player sacrifices a nontoken creature.

Industrial Advancement

At the beginning of your end step, you may sacrifice a creature. If you do, look at the top X cards of your library, where X is that creature's mana value. You may put a creature card from among them onto the battlefield. Put the rest on the bottom of your library in a random order.

Sticky Fingers

Enchant creature
Enchanted creature has menace and "Whenever this creature deals combat damage to a player, create a Treasure token." (It can't be blocked except by two or more creatures. The token is an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
When enchanted creature dies, draw a card.

Forge Devil

When Forge Devil enters the battlefield, it deals 1 damage to target creature and 1 damage to you.

Play with Fire

Play with Fire deals 2 damage to any target. If a player is dealt damage this way, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Pestilence Demon

Flying
{B}: Pestilence Demon deals 1 damage to each creature and each player.

Burning Anger

Enchant creature
Enchanted creature has "{T}: This creature deals damage equal to its power to any target."

Mirkwood Bats

Flying
Whenever you create or sacrifice a token, each opponent loses 1 life.

Fire Diamond

Fire Diamond enters the battlefield tapped.
{T}: Add {R}.

Magus of the Mirror

{T}, Sacrifice Magus of the Mirror: Exchange life totals with target opponent. Activate only during your upkeep.

Ob Nixilis Reignited

+1: You draw a card and you lose 1 life.
−3: Destroy target creature.
−8: Target opponent gets an emblem with "Whenever a player draws a card, you lose 2 life."

Passageway Seer

Lifelink
When Passageway Seer enters the battlefield, you take the initiative.
At the beginning of your end step, if you have the initiative, put a +1/+1 counter on Passageway Seer.

Elturel Survivors

Trample, myriad
As long as Elturel Survivors is attacking, it gets +X/+0, where X is the number of lands defending player controls.

Deepcavern Imp

Flying, haste
Echo—Discard a card. (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)

Devilish Valet

Trample, haste
Alliance — Whenever another creature enters the battlefield under your control, double Devilish Valet's power until end of turn.

Kitchen Imp

Flying, haste
Madness {B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Apocalypse Demon

Flying
Apocalypse Demon's power and toughness are each equal to the number of cards in your graveyard.
At the beginning of your upkeep, tap Apocalypse Demon unless you sacrifice another creature.

Everflame Eidolon

Bestow {2}{R} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
{R}: Everflame Eidolon gets +1/+0 until end of turn. If it's an Aura, enchanted creature gets +1/+0 until end of turn instead.
Enchanted creature gets +1/+1.