Recommendations for Ornamental Grass

Yes - a sibirica or an ensata Iris - both are ideal for the side of a pond. Ensata is a water Iris, so is also ideal if it's very wet. Many varieties of both types though.
Libertia is a good shout, although I find L. grandiflora a but dull. There are gold varieties, but they can be hard to keep alive in colder areas. I lost mine, and I haven't been able to find a replacement yet.