The Balrog, Durin's Bane

This spell costs {1} less to cast for each permanent sacrificed this turn.
Haste
The Balrog can't be blocked except by legendary creatures.
When The Balrog dies, destroy target artifact or creature an opponent controls.

Sauron, the Necromancer

Menace
Whenever Sauron attacks, exile target creature card from your graveyard. Create a tapped and attacking token that's a copy of that card, except it's a 3/3 black Wraith with menace. At the beginning of the next end step, exile that token unless Sauron is your Ring-bearer.

Rakdos Drake

Flying
Unleash (You may have this creature enter with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)

Testament Bearer

When this creature dies, look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.

Lambholt Harrier

{3}{R}: Target creature can't block this turn.

Taunting Kobold

Haste
Whenever this creature attacks, goad target creature an opponent controls. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)

Sanguinary Mage

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Revenant

Flying
Revenant's power and toughness are each equal to the number of creature cards in your graveyard.

Blind Zealot

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Whenever this creature deals combat damage to a player, you may sacrifice it. If you do, destroy target creature that player controls.

Satyr Rambler

Blight-Breath Catoblepas

When this creature enters, target creature an opponent controls gets -X/-X until end of turn, where X is your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Éomer of the Riddermark

Haste
Whenever Éomer attacks, if you control a creature with the greatest power among creatures on the battlefield, create a 1/1 white Human Soldier creature token.

Entropic Decay

Mill four cards. (Then exile this card. You may cast the creature later from exile.)

Gray Slaad

As long as there are four or more creature cards in your graveyard, this creature has menace and deathtouch.

Gray Slaad // Entropic Decay

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 this creature enters, each opponent sacrifices a creature.

Voldaren Stinger

This creature has first strike as long as it's attacking.
{2}{R}: This creature gets +2/+0 until end of turn.

Sarevok, Deathbringer

At the beginning of each player's end step, if no permanents left the battlefield this turn, that player loses X life, where X is Sarevok's power.
Choose a Background (You can have a Background as a second commander.)

Gore-House Chainwalker

Unleash (You may have this creature enter with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)

Lagomos, Hand of Hatred

At the beginning of combat on your turn, create a 2/1 red Elemental creature token with trample and haste. Sacrifice it at the beginning of the next end step.
{T}: Search your library for a card, put it into your hand, then shuffle. Activate only if five or more creatures died this turn.

Mirkwood Bats

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

Falkenrath Pit Fighter

{1}{R}, Discard a card, Sacrifice a Vampire: Draw two cards. Activate only if an opponent lost life this turn.

Swarm of Bloodflies

Flying
This creature enters with two +1/+1 counters on it.
Whenever another creature dies, put a +1/+1 counter on this creature.

Fearless Liberator

Boast — {2}{R}: Create a 2/1 red Dwarf Berserker creature token. (Activate only if this creature attacked this turn and only once each turn.)

Wojek Bodyguard

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
This creature can't attack or block alone.

Humble Defector

{T}: Draw two cards. Target opponent gains control of this creature. Activate only during your turn.

Goblin Swine-Rider

Whenever this creature becomes blocked, it deals 2 damage to each attacking creature and each blocking creature.

Voracious Fell Beast

Flying
When this creature enters, each opponent sacrifices a creature of their choice. Create a Food token for each creature sacrificed this way. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")

Firefiend Elemental

Haste (This creature can attack and {T} as soon as it comes under your control.)
Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)