There are different views in Dynamics 365 Applications. Some Views are just for representational purposes whereas some holds significance as a part of security permissions.

Based on my exploration, I have classified different type of Views available in Dynamics 365 applications. 

The listing of the views are as follows:

Public views are the views within the application which are accessible by all

Personal Views are the views which can be accessed only by the user who has created and the user to which these views are shared. It is represented by a person icon alongside its name.

Default views are the views which gets displayed whenever the table or entity is viewed as a part of listings. Any public views can be marked as a Default view and there can be only 1 default public view. Other view types like Lookup view, Advanced Find view, Quick Find view, Associated view can each have 1 default public view of their corresponding type.

Org chart view are the new type of view which is mostly used to display the hierarchical visual information for a specific entity. It is mostly used to represent contacts within an account. Customized hierarchies can be set based on a drag and drop authoring canvas interface.

Hierarchy View is a classic visual interface to represent a set of hierarchical relationship for an entity / table. Contacts hierarchy, Product categories etc. can be represented using this view. The hierarchy for the related records is shown in a Tree view with individual nodes represented as a tile.

Recordset view allows you to navigate to multiple records by providing a visually appealing left pane just like Inbox view navigation which is quite ubiquitous in Microsoft Office email client.

Timeline View basically represents activities, notes, email, journal etc. in a sequential fashion. Timeline view captures emails, notes, appointments, phone calls, tasks etc. Timeline view is used for task tracking and capturing recent information that are visible over a period of time.

Focused View allows you to view records in single page with more focused towards the record contents. The focused views can be used for selected tables such as contacts, lead, accounts, and opportunity records.

Subgrid views are basically represented as a Subgrid control displaying related records for a specific table. If a table has a relationship established with another table, then subgrid view can be used to display the corresponding records.

Merge Incident Views are used to control the set of fields which gets displayed when two or more cases gets merged as a part of consolidation action.

Lookup views are usually the form interface which gets rendered when a user tries to search for a content within the lookup control. Initial preview of lookup fields can also be controlled by formatting the view to display relevant columns.

Associated Child cases are basically used to render a pop-up screen which displays list of columns while establishing a parent child relationship between the cases.