Unfortunately we don't have that information, as Extension doesn't keep track of what plant suppliers are offering (and we don't make recommendations for any specific businesses). From experience, I can say that most garden centers/nurseries don't sell moss, and those that sell the "moss milkshake" type of products (moss spores in a carton that can be spread to germinate) may not have the mosses included in those products identified to species level (and may not be locally native, or at least derived from local populations, as is the ideal for native plants).

However, you may be able to propagate from mosses already colonizing your yard by dividing the clumps and pressing the pieces back onto the soil surface. It might take them awhile to re-establish since moss don't have true roots (they have root-like growths, though, that help to anchor them) and they generally grow slowly. Maryland Biodiversity Project lists several hundred moss species that occur (or are expected to occur) in Maryland. With that level of diversity, mosses can vary in their requirements for how much direct sun they receive, how evenly moist they need to stay, and what acidity (pH) the soil is beneath them. While damp, shady, acidic soil is often a good location for many commonly-seen mosses, you may find some more tolerant of sun, near-alkaline soils, and drying out.

Miri