I don't see any stepping stone path, but that yard is full of possibilities. If you share your biggest nearby city, it wil be easier to suggest plants. I you are in Virginia, one of the best places to check to see if something you like is a native plant would be the Digital Atlas of the Virginia Flora. Here is the link: native plant atlas

I would check out your nearest native plant nursery and your state's native plant society. The atlas in my link will show you in exactly which counties in VA a plant is native, but you need the name of the plant first.

Let us know your approximate location. If you look at a map, you will see the zone 7b extends from the east coast all the way across the country and up into the Pacific Northwest.

I guess I'd see about removing the line of bricks and smoothing the site. I'd replace the existing grass with creeping red fescue. A grass that works for shade. It is no mow as a ground cover, or one mov. It grows and then falls over to form tufts of invitingly soft green carpet you feel fine resting down on.

I hate to sound like no- help, but you will likely need a garden designer to help you with a comprehensive plan, so that there will be pathways, different planting areas according to patterns, and the plant selection for those areas— deciding on different heights & characteristics also. And being realistic about whether you want to “ play in the dirt “ in some areas or have the lowest maintenance even if a bit less varied. Even if, as is said many times, you don’t install all at once. It matters where you go in & out of house, where would be the best place for sitting, what times of year ( sun, temps, bugs.)

I love how private your yard is. Beautiful trees! Like marmiegard, I would recommend that you talk to a designer, mostly because of the change in grade and retaining wall that cuts your yard in two. Good luck!

From here, the retaining wall is a huge feature in your yard. Getting rid of it would solve a lot of problems, but I'm guessing it's there for a reason. If I were designing a garden for you, with that retaining wall as is, I'd put in a path/divider giving you essentially 3 wedges/pie slices I'd have the 3 wedges end in a feature. Maybe a patio with a fire pit, maybe a fountain, maybe a sculpture like an armillary sphere.

If you kept the two right-most wedges as grass, I'd plant up their right edges (ie the wood fence and the brick wall). They, you could have the leftmost wedge garden.

Intentionally embracing the wedge would make the whole thing cohesive, instead of having a yard kind of split in two odd pieces. Now, of course, that impression might be a function of the camera angle and you might not notice it when you are in your yard.

I'd probably go with ferns in your back corner. Marginal wood fern and Christmas fern can both cope with a bit of dry shade. You will need to water them if it's really dry, but they don't need the swampy conditions many ferns prefer. Tiarella is a pretty ground cover that does well of me in dry shade. Heartleaf aster and goatsbeard do well, too..

Some idea

Or with some overhang and sitting area