Since you have mostly block shapes in your beautiful quilt I would go with a circular motif like a wreath in the green spaces. I think I would also use the same color thread in the green spaces since you have so much color going on throughout the quilt. I love the pattern and I wonder if it had a name or if you designed the pattern. I have made 3 scrap quilts this year and I still have 3 bins of scraps left that I could use to make this quilt. Great job!