I would put a small Anubias (my choice) or java fern on a little piece of driftwood. You would get some dark brown color out of the wood (to balance the bright sand) and some actual leaves (to balance the 'fuzzy' moss). Both would be happy enough under minimal light and slow growing.
That would give you 2 little 'islands' in the sand and still maintain the minimalist thing it look like you have going.
I added a piece of cholla wood, trying to stay away from dw or plants that cant be stuck in the ground. I do like the idea of having some leaves to balance things out though
I laughed pretty hard too ha.. You can try crypts; they're slow and low so wouldn't crowd out the bowl. If you want something that grows out as a bush you can try hemianthus micranthemoides/glomeratus, but that'd take up more space. Stem plants that will grow out and flower that are not too weedy; Bacopa colorata/carolina with blue flowers, Proserpinaca palustris or perhaps lobelia cardinalis. All these can be grown in soil tanks without CO2.
What Bacopa has blue flowers?? I cant find any with those names, one is red and the other is green?
I like the lobelia cardinalis, might be a good fit.
Why did you add potting soil, are you going to plant stem plants..?
I added it because I wasnt sure what I was going to do, and didnt want to not have something later down the road... if I dont end up using it, then oh well right?
I have some Elodea, but I feel like that is too tall of a plant for this setup. I also have some narrow leaf java fern but like I said trying to stay away from driftwood or plants that cant be planted into the ground. Thanks everyone for the comments so far...