Is there any automation where we can create dummy data for a newly created org. If i have a excel sheet with multiple sheets in it. Like Account, Contact, Opportunity can we import it.
You could take advantage of the new feature to run a script when a sandbox is created or refreshed. You can find details about the feature in the latest release notes. I would run some apex code that will insert generic accounts or contacts or call an external system that has that spreadsheet uploaded or even a database.