Well, take the chromatic scale, 12 notes. Make the 5 notes scales, you have the major, the minor, and the hybrid ones. Some aren't really interesting, while others can be found in some countries repertoire.
Then, the 6 notes (the blues scale is in this one)
the 7 notes (major, minor, and the modes, among others)
the 8,9,10,11 notes, then back to chromatic.

Then you have the scales that are larger than an octave. (say you play a note in the first octave, and you don't in the other one) that leaves of bunck of possibilities.

Allan's amazing job is to actually play the CHORDS of those scales, in unplayabale voicings, (up to 8 cases stretches) they are quite dissonant, but after a while, when you get used to them, they are way more emotionally powerful than standard scales.