Demon's Jester

Flying
Hellbent — Demon's Jester gets +2/+1 as long as you have no cards in hand.

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.)

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.)

Pitchburn Devils

When Pitchburn Devils dies, it deals 3 damage to any target.

Forge Devil

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

Auntie Blyte, Bad Influence

Flying
Whenever a source you control deals damage to you, put that many +1/+1 counters on Auntie Blyte, Bad Influence.
{1}{R}, {T}, Remove X +1/+1 counters from Auntie Blyte: It deals X damage to any target.

Blight Keeper

Flying
{7}{B}, {T}, Sacrifice Blight Keeper: Target opponent loses 4 life and you gain 4 life.

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.)

Havoc Devils

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Cadaver Imp

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

Cackling Imp

Infernal Pet

Whenever you cast your second spell each turn, put a +1/+1 counter on Infernal Pet and it gains flying until end of turn.

Carrion Imp

Flying
When Carrion Imp enters, you may exile target creature card from a graveyard. If you do, you gain 2 life.

Vexing Devil

When Vexing Devil enters, any opponent may have it deal 4 damage to them. If a player does, sacrifice Vexing Devil.

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.)

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."

Goremand

As an additional cost to cast this spell, sacrifice a creature.
Flying
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
When Goremand enters, each opponent sacrifices a creature.