Their chord progressions are usually blues based. They like heavy use of power chords, or regular barre chords distorted heavily. Sometimes they use a lot of suspended chords. This means they play a chord using the root and a chord tone with an extra note usually one step above the root or one or more steps above the first one. Some examples are:
-E7sus4=E-G#-B-D
-Csus2=C-E-F