Another nice low light floater is Ceratopteris. They can get a bit bigger, and develop nice big hanging root systems that many fish love to hang out in. Various Ceratopteris species are often called Watersprite. But watch out since sometimes a LFS will call Wisteria watersprite. Ceratopteris looks quite different immersed as opposed to floating. Submersed Ceratopteris thalictroides can look a bit like Wisteria, which I suppose is where the error comes from. Find floating watersprite and you will be safe.
Depending on the laws where you live in Salvinia and Duckweed may be easier or harder to find. They are both seriously invasive menaces in the wild, and some places crack down on selling them, especially those that have waterways that are stuck budgeting money clearing waterways smothered by them.