In a recent coursera lecture, Gary Burton identified the Lydian,
Ionian, Mixolydian, Dorian, Aeolian, Phrygian, Locrian, Lydian flat
7th, Altered and Symmetrical Diminished as the ten most important
scales. Each can be played in twelve different keys, and if you play
a string instrument, you may want to play each starting on up to twelve
different frets, for a total of 1440 different scales per instrument.
This little tool may help to avoid having to count frets for all these scales (and several other scale like things I found on wikipedia) ...
Select a key, a scale, a start fret and an instrument to get a
diagram of the corresponding scale. Optionally, you can specify a
number of frets to skip on every string if you want a diagonal scale
pattern to reach higher notes.
Source is available on github.