Power metal is more traditional metal but with clean vocals (no growls). Bands include DragonForce, Angra, Helloween, Stratovarius
There's also progressive metal, where the emphasis is more on the intricate instrumentals, so some banda don't do growls. It is usually less heavier than traditional metal. Bands include Dream Theatre, Liquid Tension Experiment, Symphony X, Tessaract, Haken, frost*, Porcupine Tree
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