What are some slow brooding riffs for guitar?

Question:preferably rock. to play on electric.

Best Answer - Chosen by Asker: preferably rock. to play on electric.

well...
palm muting makes for excellent brooding chords.
detune to C....that works.
instead of changing keys in 5ths, change up to a 4th...
(like....G - B# instead of G - C)
The band of your namesake, Silverchair, used an excellently chunky power chord in their first single...Frog Stomp? For example, the C power chord, but barre the G into it as well. (C5 add G?)