If it is possible to have running water in your yard, create a rock waterfall. Make sure it isn't much bigger than your fence line; otherwise it will look out of place. A waterfall adds a quiet sophistication to your yard with the relaxing sound of running water. The presence of water will also add some diversity to a landscape dominated by rocks and stones.
Put colorful stones in your yard in place of plants. Rocks and stones come in all different shapes and sizes, so you can use them much like you would flowers. Group them together or scatter the colors, depending on what you like. You can also paint stones to achieve the color you want, but be aware that this will not look natural.
Create a pathway through your yard using stones or gravel. Use small black or white stones to line the pathway where you want people to walk. Make sure it is wide enough for two people to stroll along. Another option is to stagger stepping stones throughout the yard that people can walk on. Make sure they are smooth, level rocks that are easy to stand on.