Sorry for the late response, I didn't see your message earlier unfortunately. The list of shipped User-Agents was recently updated. I do not plan on extending the shipped User-Agent list, since maintaining it is quite a bit of work and don't want to add any obscure entries.

You can, however, add you own entries in the settings (Menu → Add-Ons → Extensions → User-Agent-Switcher → Preferences). In order to find the strings you need I'd suggest looking at http://useragentstring.com/pages/useragentstring.php which has a very big list of those (they are not always up-to-date however).

Sincerely, Alexander