Use Visualforce pages as dashboard components. A dashboard shows data from source reports as visual components, such as charts, gauges, tables, metrics, or Visualforce pages. The components provide a snapshot of key metrics and performance indicators. Each dashboard can have up to 20 components.
Visualforce pages as dashboard components are only available in Salesforce Classic. In Lightning Experience, you can create a custom tab and use that as a dashboard for your custom lightning components.
To be included in a dashboard, a Visualforce page must use a custom controller, use a standard or custom list controller, or not have a controller. You can’t add a Visualforce page with a standard controller to a dashboard. Only Visualforce pages that meet these requirements appear as options in the Data Sources tab.