Forge Devil-DKA-C.
Two of Torch Fiend-DKA-C (one from the pack).
Bloodcrazed Neonate-ISD-C.
Pitchbirn Devils-ISD-C.
The other seven creatures are three good ones, and I would have to add lower powered cards for the rest:
Two of Goblin Arsonist-M13-C (a reprint): When Goblin Arsonist dies, you may have it deal 1 damage to target creature or player.
Falkenrath Exterminator-AVR-U: Whenever Falkenrath Exterminator deals combat damage to a player, put a +1/+1 counter on it.
Red is a color rich in Sorceries, Instants, and Enchantments for all those aggro decks that play very few creatures.
I pick five Sorceries:
Two of Pillar of Flame-AVR-C (a crowd favorite).
Demolish-AVR-C.
Krenko's Command-M13-C: Put two 1/1 tokens onto the battlefield.
Flames of the Firebrand-M13-U: Deals 3 damage divided among one, two, or three creatures or players.
I pick nine Instants: Red has great ones.
Two of Brimstone Volley-ISD-C (one from the booster pack).
Geistflame-ISD-C.
Two of Searing Spear-M13-C: Deals 3 damage to creature or player.
Chandra's Fury-M13-C: Deals 4 damage to player and 1 damage to each creature that player controls. It has a five mana cost but this is a very useful card to clear the battlefield of tokens.
Thunderous Wrath-AVR-U (miracle): Deals 5 damage to creature or player.
Thunderbolt-AVR-C.
Volcanic Geiser-M13-U: Deals X damage to target creature or player.
...and, last but not least:
Furor of the Bitten-ISD-C (from the booster pack).