I made one that my hubby picked as a kit. I wasn't really paying attention when he picked it out. Many of the fabrics are the same print in different colors, almost all the patterns are the same scale. When I put it together, I didn't like it. It was very blah. Not enough variance in the scale to be pretty. I've put it aside for over a year now...I'll finish it some day. Maybe some applique will spruce it up. But my heart wasn't in it at the time, so I put it aside for prettier ones.
I'd suggest at least 9 or so different prints, varying the scale of the prints, include some tone on tone or marbles. If you do a Google search and click "images" at the top, you will see a wide variety of samples to inspire you.