If you are using the 3rd Party Extension JCE Editor with your Joomla 3 installation, you can add additional fonts for selecting from the Font Family pulldown selector.

Components -> JCE Editor -> Editor Profiles -> Default (or Front End, Blogger, Mobile) -> Editor Parameters tab -> Typography -> Additional Fonts (near the bottom)

You can add additional fonts here if you want your users to have access to them. If you are using fonts other thatn the standard list, they must be linked to in your indes.php file or in your stylesheets using @font.

You may also remove fonts in the next option if you don't want your contributers to have access to these fonts.