David Baker, in his books often likes to write of "Bebop Scales" - - actually, you can create any number of 8 note scales by simply adding a tone on an off beat then exploring the implications of it.
I like to add b9s and b5s in a lot of scales I play...
You can also add more than one passing tone...
ex. F F# G A Bb B C D Eb F count - - 1 uh2 3 4 | uh1 2 3 4
In theory, you can also "rhythmically transpose" entire chromatic scales so the "on beat" notes outline conventional scales (or to put it the opposite way - - play a regular scale, but using the entire chromatic scale.)
ex.
D D# E F F# G G# A A# B C C# D
Count - - 1 uh2 3 uh4 | uh1 uh2 3 uh4
In theory you can take any scale and rhythmically arrange it so the tones of a chroamtic scale will outline it - - but this is all "academic" - -
At first its best to just practice adding tones... Get the feel and the fingering and hear how they sound.