Google Docs has lots of templates but the funny part is they are not well integrated with the individual components, instead you almost have to go to the templates directory first and then to a particular class of document (like presentation)
Within Google Docs presentation, there is no way to go to templates library at https://docs.google.com/templates pictured above
and thats all it shows.
Instead you need to go to the Google Docs homepage and then choose templates. This is slightly opposite to the way people use Office software- you generally decide to use a software and then use a template. Not with Google Docs though- you need to choose template first using either of three methods-