Red Aggro is a popular Standard deck following the old Strategy of Red Deck Wins. It tries to deal as much damage to its opponent as fast as possible using burn spells and quick creatures. Its cousin Blightning Aggro splashes black for the spell Blightning along with other black spells.
Sample decklist of Red Deck Wins as piloted by Sami Haggkvist at Worlds 2008:
Blightning Aggro, as piloted to 3rd place at Worlds 2008 by Tsuyoshi Ikeda: