To see what font packages you have, double-click on the TEXFonts icon. A directory viewer will open showing the standard TEXFonts packages and 3rdParty and User directories.
The 3rdParty directory will contain any font packages that are not part of the standard TEXFonts distribution.
The User directory contains your own fonts; section
explains how to add your own fonts in more detail.
Each font package is an application. It should have a !Help file to explain the fonts it contains and any restrictions on their use. Double-clicking on the package will (usually) open a directory viewer showing the fonts in the package.