It is amazing how often that happens. I am not a fan of the color orange, but, I made a fishing quilt for a new nephew and the fabric was a blue and orange fish print. It turned out to be one of my favorite baby quilts! I like your quilt because it not only has so many colors but also a variety of sizes of prints. It gives it a very textural feeling. For this one, I would use a darker color to frame it out. Use your favorite. Are you more of a blue person? green? or brown person? If so, I would use a pure blue(more royal than navy) or a deep hunter green or a dark chocolate. If you need a larger border area, perhaps use 2 of these colors for a double border (the inner the same size as you small squares and the outer one 2 or 2 1/2 times that size.