I'm a self taught developing guitarist who plays a lot of 'three chord' songs.   I play lots of songs in the Keys of C, E, A, G and D. My question: When for example, playing in the key of G, what other chords, etc. can I add to G, C and D chords to make each song sound different. I haven't really tackled barre chords yet. I strum and fingerpick, so that helps songs sound different in some cases.

Peace,
Anne