You can use stem plants in a sand-only substrate. A lot of stems can feed off the water column such as Limnophila sessiliflora, Hornwort, and Elodea. You don't even need to plant them in the sand, just weigh them down with a plant weight on the substrate surface or even plant them in terracotta pots for example. You can also use them as floating plants if you want.
As for epiphyte alternatives, you could try smaller Anubias, Java Fern, Bolbitis, Buceplhradrana and Schismatoglottis prietoi.