Diminished, harmonic minor, melodic minor, blues scale, double harmonic major, alternate scale/super locrian.
Which one you can use depends on the chord you’re playing over. Generally speaking the harmonic minor, melodic minor and the blues scale work over the m6 chord, diminished, double harmonic major and super locrian work over the dominant seven chord. What to use over major6 chords I’m still not really sure because I usually play over either minor swing or Les yeux Noir and they only have minor 6 chords and dominant 7 chords.
Gypsy is not scale based. It’s arpeggio based. Learn major arps (and Ma7 arps) also – AND THIS IS THE BIG ONE – min6 arps (As well as min9 arps) – which can be used over minor chords AND 9th chords, (an Amin6 arp works over Am and D9). Also diminished arps and dim scales work over the V chord. Play an F dim arp over an E7 chord, (think 1/2 step up). Lastly, the Phrygian Dominant scale (5th mode of harm min) works well over the V as well.