Meaning of different tokens in a font config string

xfontsel will allow you to view, select and adjust all of these fields:

You can also use the command xlsfonts to see a list of installed fonts. This will list all fonts, so you may want to pipe it through grep to view required subsets, eg,: xlsfonts | grep droid

Similarly, fc-list will display a list of all installed fonts.

You can read more about the differences between core and Xft fonts here: http://en.wikibooks.org/wiki/Guide_to_X11/Fonts#Core_versus_Xft_fonts

The former is a X logical font descriptor; the linked article describes each field. The xfontsel tool can help you create a XLFD interactively.

The latter is a Xft font name. While there are API calls for enumerating the various fonts, I don't know of any tool that exposes it since most have changed over to Fontconfig already.