Following up on my earlier posting, where I listed some excellent choices for adding color to shady spots in your garden, here's a few favorites that stay low. Some can even be used as ground covers.
Ajuga reptans. Whether you go for the green or the chocolate tones, ajugas are tough, low water plants that are good for adding a bit of texture to a shady spot. Plus, purple flowers!
Asarum canadense. One of my favorite shade ground covers. Known as BC ginger, this fast spreading GC with the heart-shaped verdant green leaves also offers as a bonus cute, oddly colored flowers. The Panda Face variety has leathery brown & eggplant flowers that one can only call weird.
Bergenia. An oldie but goody, this plant is an excellent choice for adding masses of green foliage as an understory planting. It has pink and white flowering varieties.
Campanula muralis. A popular and surprisingly resilient GC that once settled in provides lots of cheerful purple flowers over a long season. Charming kidney-shaped, toothed leaves add to its appeal.
Carex. There are quite a few sedges that can handle a fair amount of shade, though not dark shade. They offer grass-like textures in a variety of light greens and golds. Hardy, attractive, versatile.