If you end up with 0 nitrates the plants in the filter will generally show it pretty quickly. I like to keep ~5ppm nitrates in my tanks for best growth but the amount of nitrates can range from 0-20 in a healthy tank usually.
The plants are all terrestrial or semi-aquatic. I've got pohothos, arrowhead, philodendron, mondo grass, pace lily, and two young Bolbitis heteroclita in that particular filter right now. I had wandering jew and golden club but those were removed last week to make some rooting space for the bolbitis. I need to thin it out again, I'll probably cut back the pothos and remove some of the mondo grass bunches.
Usually just about anything can be rooted in the filters but if you want something long-term you'll want to get semi-aquatics or terrestrials that can handle wet feet.