Do you plan on it being a wall hanging or a quilt to keep someone warm?
I would do different and opposing filler designs in each of the elements ... but nothing "formal". Ripples, pebbles, meanders, swirls, mctavish ... etc. By "opposing" I mean that each section that touches each other has either a pattern in a different direction or patterns that "clash" (ripples next to swirls for example).
If it's going to be a quilt to keep a body warm I would use perhaps no more than 3-4 different designs and quilt them fairly loosely.
If it's going to be a wall hanging I would choose a wider variety - 5-7, and quilt it more densely.