There are not many instruments that can do full chording. Look at the Orchestra: The piano(sometime considerd persussion), harp, and mallet percussion are the main ones. There are some uses of other keyboards like celeste and harpsichord (this is also a plectrum instrument). The stings can chord but not that easy. You usually need several to play a chord. Also, you have guitar and the related plecturm family for chording.
IMHO the majority of instruments are single line in function.
The diatonic and chromatic harmonicas have some chord function but limited compared to the major players like piano(keyboard) and harp. The chord harmonica can fill the role but is limited in its voicings.
My approach is mostly single line in the creation of melodies as an improvisor. This can be the major part of the music or a supportive line. I can also supply color in an array of shades. Moods sweet and savory.
---------- Emile "Diggs" D'Amico a Legend In His Own Mind How you doin'
