AutoCAD fonts are stored in SHX files. Recent versions of AutoCAD may have more AutoCAD fonts files compared older versions, but if you are still not satisfied with the number of fonts AutoCAD is putting to your use, here is a trick you need to consider using.
autocad linetype Archive
Every linetype in AutoCAD is stored in .lin files. Only one linetype is loaded in your design when you open a new project in AutoCAD. To have access to other linetypes, you will have to load them manually. Loading a new linetype (Using of the LT command)