Odoo has many different view types. Each has a different function.
Remember that each view is for one Model (database table), but can also show data from related models.
Tree or List
Also known as a List View, this is used extensively in Odoo. Technical information.

Kanban
Another way of displaying multiple records is to use the Kanban view

Kanban is a Japanese concept of using cards on a board to have a visual representation of activities (in a just-in-time or lean production process).
A “kanban view” is therefore a series of cards with key information highlighted. Cards can be moved (by ‘drag and drop’), so in the above example a Sales Lead could be moved from “New” to “Qualified” using a mouse.
This can be used as part of a workflow solution.
Related: Adding a Kanban View using Odoo Studio
Form
This is primarily designed to show one record from a single Model (database table) but it can also show a great deal of associated data from other Models, for example with Products:

Related: Odoo Form View
Search
Search Views cannot be displayed on their own. They are used with other views to provide a search function.

There are three types of search:
- Autocomplete (e.g. type “Desk” in search box)
- Filters
- Group By

Note: user-defined filters are displayed in the Favourites drop-down menu. These are not defined in Search Views. Users can create and save them, or an administrator can set them up.
QWeb
This is used for reports and web pages.
Activity
This is a grid showing Activities. For example, the CRM pipeline:

Activities can be recorded in the “chatter” section on a Form View.
Calendar
Displays records as events in a daily, weekly or monthly calendar
- dates need to be specified (e.g. start date, end date)

Dashboard
Currently only available in Odoo Enterprise

Gantt
Only available in Enterprise. Primarily used in the Project app and in Manufacturing. Designed to show a series of activities with start and end dates. Technical information.
Pivot
Used for data analysis

Graph

Grid
This is primarily used with Analytic Accounts:

Map
New in Odoo 13 and currently only available in Odoo Enterprise.

Cohort
This was introduced in Odoo 12 and is currently only available in Odoo Enterprise. It can be used to analyze data over a period of time:

Odoo technical documentation
https://www.odoo.com/documentation/13.0/reference/views.html