there are lots of mosses out there... lets see... im not that great at plant names... go to home depo and look at their plants.. they usually have a really good selection surprisingly the tags on the give specifics usually also blackjungle.. that company's sight is awsome.. google it to get sight...
Definately check out home depot. You can buy some great plants for like $2.50 a piece. You could use plants like cryptanthus, philodendron, maybe a small fern or two, and a whole variety of others (all of which I have bought from home depot). There are many plants that will outgrow an 2 gallon (not sure of the dimensions of an 2 gallon) but you can probably house them for a good year or so before having to remove them, like spider plants, some bromeliads, orchids, etc. And yes, you can use air plants, in fact I highly recomend you do, they look really great, and you can get them really small. And as Fish Newb pointed out there are various mosses you can use, although they can sometimes be difficult to keep alive. If you'd like to order online, sites like blackjungle.com, cloudjungle.com, or T&C terrariums(http://home.att.net/~a.j.calisi/catalog.html) have good selections.
Well, good luck!
0.4.3 D. leucomelas
0.1.0 D. imitator
0.0.3 D. tinctorius 'Alanis'
1.1.0 D. tinctorius 'Surinam Cobalt'
1.1.0 D. pumilio 'El Dorado'
1.1.0 D. pumilio 'Golddust Bastimentos' TANK PICS