I have a 10g that's working on indirect lighting only and yet the growth has been pretty lush so far. Java fern, mosses, hornwort, anubias, water sprite, echinodorus vesuvius will all work. Even hygrophila polysperma grows really well in the areas that get a little more light (and I do mean a *little*) to the point where I have to trim them every few weeks.
Stay away from any high light plants like cabomba and bacopa and you should be ok. Often the high light plants will still grow in a low light tank but they'll grow with fewer leaves at the bottom, or grow slower, or will not have the red color that they would in a high light tank.