A: 24 Scales at the Guitar Seat

One root, every type. Pick the one that fits the chord you are on.

Every scale type this site maps, rooted on A and laid out at this seat. The modes of the major scale do most of the work over most of the repertoire; the rest are here for the bar where a dominant refuses to behave.

A guitar chorus is a single line with the comp dropped, so a scale here is what the picking hand walks through between the two or three phrases it actually meant to play.