It's a very simple powershell which can be used to fetch all the lists from a site and show the total count of list items in each list.  It will list all the system and hidden lists on the site.

The script file has function GetListItemCount which take site URL as parameter and will return the list details;

You can call the function and can save data in CSV file or can also view grid view.

 

PowerShell
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GetListItemCount "https://MSTalk.sharepoint.com/"| Out-GridView
 OR
PowerShell
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GetListItemCount "https://MSTalk.sharepoint.com"| ExportCsv -Path "C:\itemcount.csv"
 you will get the below output: