External list are useful to create external data in SharePoint 2013. To create an external list follow below steps:
Open your SharePoint site, navigate to Settings and click on Add an app as shown in the figure below:
The above step will open the Apps home page. From the Apps home page select External List as shown in the figure below:
This will open the Add external list dialog box, Here give a name of the external list and you can chose the data source for that. Here also you can click on the External Content Type Picker and there you can chose the external content type and click on Ok as shown in the figure below:
Then click on the Create button, this will create the external list as well as it will show the data of that external list.