Joomla AdminController: It is base class for a Joomla Administrator Controller. This class extends BaseController.
Joomla AdminModel: It is a prototype admin model. This class extends Form Model, which extends Base Database Model.
Joomla Application Class: SiteApplication and Administrator application classes extend CMSApplication class.
Joomla BaseController: It is the base class for a Joomla Controller. Controllers are where you put all the actual code. It provides basic functionality, such as rendering views (displaying templates).
Location: libraries/src/MVC/Controller
Joomla BaseDatabaseModel: It is Base class for a database Joomla Model. It acts as a Factory class for application specific objects and provides many supporting API functions.
Joomla FormController: This controller is used for the most of form-based admin operations. This class extends BaseController.
Joomla FormModel: It is a prototype form model. This class extends Base Database Model.
Joomla HtmlView: It is a base class for a Joomla View. It is a class holding methods for displaying presentation data.
Updates for Joomla CMS
Joomla ListModel: It is a model class for handling lists of items. This class extends Base Database Model.