#2
Pentatonic minor scale
Blues scale (same as ^ but with a diminished fifth also)

Groove on.
#3
and the good ol' devils interval, the tritone is powerful...used by black sabbath plenty
E G A A# on the E string or --0--3--5--6--
Well, they cant all be winners
#4
Excuse me if I am wrong because I am pretty new to all of this but... did you not just describe the blues scale that the poster above you stated?