There are several patches of grass in the yard that are distinctly different from the fescue. It is very dense, enough to discourage weeds. Looks like a bunch type at the root, and very durable. Deep green color all year, makes me think of a bluegrass, but I can't identify the seed head. Head is a single stem with little pinkish purple globes tightly arranged. Well behaved, and slowly spreading; I like it a lot and would seed it around if its a desirable species. What is it?
Arlington County Virginia lawns and turf
This looks like liriope, which is actually not a grass. it is a good alternative ground cover which rarely needs fertilizer. If you choose not to mow it gets 9-14 inches tall, not including the flow spike, depending on the variety.
I've never seen liriope in seed form sold commercially. You can buy starts - there are a couple of species out there with different foliage colors ranging from like to dark green.
In the fall it will get BB size dark seeds on the flower spike. You can strip those off in late fall and spread them in an area you want to have liriope, but the germination rates, in my experience are very low. You can also dig up some of your plants, divide them and transplant them.
Generally, once established it has decent resistance to drought, rarely needs fertilizer and provides a nice unifying element to the landscape. It does not have the wear resistance to foot traffic that turf does. You'll want to establish mulch paths or use stepping stones in high traffic areas. it does not handle close mowing well. It can have disease issues especially when the canopy is tight. These tend to be more cosmetic than lethal. It can be cut in late winter/early spring to encourage new growth in the spring.