It depends. Foliage, or flowers? Shade, or sun? Wet clay, or dry sand? Look into ivy, juniper, Asiatic jasmine for foliage. Creeping jenny, daylilies, coral bells, and vincas provide flowers.
You can use creeping charlie or ground ivy plant. This type of plant belong to mint family and thrives in shaded areas and in open areas where sunlight is present.
Well try to go for some bushy plants. That will most likely cover the whole area and if it gets too big then you can cut them off at any time. I really like daisies as well. Daisies are also very good for covering big areas and substances so plant those.
