FL CommunityFans I have Anubias and Crypts in gravel and sand. The Crypts do well in both substrates though you may have to use plant tabs under them in the sand as the fish poo doesn't sink down into it like it does in gravel.
I have Anubias in both substrates also but I don't have to use plant tabs in the gravel for either plants. Since Anubias doesn't usually take well to being buried I weight mine down with a rock and they will grow roots down into the gravel and sand to anchor themselves. So I think they get a lot of their nutrients from the water.
Anubias can be attached to rooks or wood, Java Fern and Java Moss need to be attached to wood or rocks and are not really particular about water conditions. One note of caution

The Java Moss will go everywhere if your not careful, so when you trim it catch every stray tiny piece of moss

Another low light plant I don't see used much and is super easy is bolbitis Heudelotti.
http://www.plantgeek.net/plantguide_viewer.php?id=40 I have used this plant for years and love it. although the profile says it does better with CO2 I have never used it and the plant still did really well. It also has to be attached to rocks or wood.
Carol