Here is a metal guitar riff in Drop A tuning A E A D F# B. This lick has a kind of exotic sound that reminds me a bit of the phyrgian mode but I haven't analyzed the notes in terms of a particular scale this just sounded interesting to me. The video demonstrates the lick alone and over a drum backing track. There is also a right hand view and a slower speed demonstration. The bulk of the lick is made up of symmetrical legato patterns.
