You can get a lot of mileage by playing single string out of the 7th fret bar chord shape in D. Check it out! Also, a little re-harmonization can go along way. All the chord changes are based off notes in the melody. Just as you can create melodic variations, you can also create chordal variations. This is something fun to do with a band, but not a great idea to throw in a crazy new chord progression at a jam...
