I use the guitar mostly for song accompaniment, but I also play some classical guitar (and use a classic guitar to back my singing).

Depending on the song, I may play chords and rhythm only, OR I may work in countermelodies or harmonic lines to the tune of the song. Even with straight rhythm, say "Burl Ives Basic" (bump-chug-chug, bump-chug-chug). I generally plan the bass notes (the "bump" part of the pattern) carefully.

I know a number of folk guitarists who do the same.

Don Firth