I thought it would be a good idea to have a list of COMMON plants that are suited to vivariums. Stuff that one can find easily just by walking into a nursery or hardware store with a garden department. Most of them are houseplants, but I'd imagine there are others that aren't. I'm hoping people will add info to this thread based on their own experience. Since common names differ, I'll try and put in the scientific names, plus some info and a pic. Anyway, here are the plants I've worked with.
Heart Leaf Philodendron - Philodendron scandens: This is a plant with a climbing/creeping habit. It is a fast and aggressive grower, you will need to keep it pruned. But since it can easily be propogated by clippings, you can use them to start new plants. Very distinctive with its dark green or varigated heart shape leaves.
Pothos - Epipremnum aureum (also Scindapsus aures): Another hardy, fast growing plant that needs to be pruned often. The leaves are waxier and larger than P. scandens, and have a less defined heart shape. Comes in a variety of colors.
Weeping Fig - Ficus pumila: A popular vivarium plant. It also has a creeping/climbing habit, but grows slightly slower than P. scandens or E. aureum. It also has a woody stem that the others lack. Will have to be pruned, but not quite as often in my experience. This plant has two different style of leaves. The immature leaf form is about the size of a nickle, and spade shaped with a ruffled surface. The mature plant has larger, smooth almond shaped leaves.
Note: All of these plants are very hardy, provided they get enough light. In fact, they're so hardy, you'll probably find yourself cutting them back fairly often so they don't strangle everything else. Very good for covering backgrounds, though.
Maidenhair Fern (also Maiden Hair Fern)- Adiantum tenerum: This plant comes in several forms. The one I use is pictured below. A hardy fern that can be mounted as an epiphyte as long as they don't dry out, or planted in the soil provided that it doesn't stay too wet. They like it moist, not soggy. Fairly slow growing, also stays fairly small, maximum height 8-12". The plant is from South America, so if you're trying to build a viv with native South American plants, it's very possible that darts encounter this plant in the wild. It's definitely worth a look.
Fittonia (also Nerve Plant) - Fittonia argyroneura: This is not the plant that drops over when you touch it. The leaves are dark green, with viens that come in many different colors. I have the 'silver vein' version, but it also comes in some striking variations, such as red, pink, and even purple. Like the Maidenhair, this plant comes from SA, specifically Peru. It likes high humidity (at least 65%) and also likes moist soil. It cannot stand up to temps less than 60 degrees, and that is where it gets its name. If you let it get cold, it dies. Don't leave it in your car in the winter while you go inside.
That's all I can type for now. I'll add more to this list later.