Certainly a lot of easier guitar parts are written in keys that make guitar playing easier. That's the point! A lot of studies - Carcassi, etc., are written in keys which allow open strings to be held as pedal notes to accompany other more intricate parts to be played on upper strings.
Thus keys of E, A and D (and their parallel and occasional relative minors) are commonplace. C and G also feature, as any of the open strings on guitar are diatonic to those keys in particular.
There's also, moving away from the classical side, a lot of electric guitar stuff which sounds better using open strings underneath - hence keys of E, A and D being used a lot. Also E♭ and D crop up when guitars are downtuned.
Looking at other music, the majority of it will be in the original key. Which means a lot of jazz could well be in B♭ or E♭, which is where a guitarist will often find himself. I guess at that point in his playing, he'll be well versed in barres or partial chords, and not have to rely on open strings. Having the luxury of a bass player also obviates this! One reason being vibrato isn't that easy to apply to open strings, and playing a single open string in the middle of a phrase sounds different from the others.
So, yes, there's a lot of 'open string' keys - particularly in beginner type guitar music, and also to utilise the fact that open bass string notes give more freedom for the fingers to play elsewhere on the fretboard, but in some genres, it hardly exists. Also, if a song has been 'written' on guitar, there's a good chance it won't be in B♭, E♭, F♯, C♯, et al!
EDIT - I wrote this answer on the premise of keys that guitar music/tabs are written in - but now it appears you're asking about chords whose root notes aren't C,G,D,A,E etc.
There are many chords in songs which have sharps. e.g. C♯ m, G♯m F♯m, which belong to the keys quoted. In fact, all three are diatonic chords in key E - a very common guitar key. So, yes, they will all appear from time to time. True, there won't be as many B♭, E♭ A♭ rooted chords, because they aren't found in keys favoured by a lot of guitarists. However, as earlier in this answer, they will be found in songs in original keys such as those just mentioned. Along with several minors which actually sound simple - Cm, Gm, Fm, but wouldn't be included in beginner guitar songs if possible.