The family Amanitaceae contains some of the most deadly mushrooms in the world (the death angel and destroying angel). Other possibly deadly forms like the fly agaric are considered hallucinogenic. Still others in this taxa are wonderfully delicious. In total there are about 815 named species, although that number has been increasing by about one every year. There may be as many as 1000 species before we're done counting.
The family contains only two genera, Amanita (with about 765 species) and Limacella (currently 50 species). For a detailed overview of distinctions between the genera, we recommend Amanitaceae.org [1]. They have several pages dedicated to every aspect of the family, including descriptions of every species.
Links:
[1] http://www.amanitaceae.org/