As far as I’m concerned, because of my musical path, for a long time I gave little consideration to scales with open strings. I see that this happens to many guitarists, especially to those who play very distorted musical styles (which was the case with me too). This is certainly due to the fact that they need to constantly keep all those noisy signals under control.
That’s why I started to appreciate the tonal possibilities derived from playing with open strings only at a later stage.
To start off, right now what I’m going to do is to take the 12 major scales and ordering them from those who allow the use of all the six strings of the guitar (if your guitar has more strings I can’t help you) to that of C#/Db who allows none.
As I said at the beginning, C#/Db is the only scale that make no use of open strings, but I have to admit that people usually tend not to play their songs in this tonality.