13th chords for guitar
A full 13th chord is made up of seven notes. That is a major triad plus a seventh, ninth, eleventh and the 13th. Since this is impossible to play on a six-string guitar, the fifth and the third are often left out (and sometimes even the root). E.g. C13 consists of the notes C, E, G, Bb, D, F and A.
Scale fit: Mixolydian, Lydian b7