Watch the Power Chords online guitar lesson by Joe Dalton from Fretboard Epiphanies
Power chords with drones and/or open strings have some new exciting sounds. Look for other sounds with two string power chords. Try different frets and other strings. Notice how I have set up different patterns and phrases. All of these are of the simple variety. You should be able to identify the pattern through analysis. Try to create your own. This will help you find your own voice as an artist.