Recently I found a nice resource on TechNet about the naming conventions for service accounts and best practices for some of these accounts. You can access the whole article on TechNet: SharePoint 2013 Best Practices: Service Accounts (en-US)
- SQL_Service, for the SQL Server service.
- SQL_Admin, for the SQL Server administrator.
- SP_Admin, for the SharePoint administrator and setup user.
- SP_Farm, for the SharePoint farm service.
- SP_WebApps, for the user-facing web application app pool.
- SP_ServiceApps, for the service application app pool.
- SP_Crawl, default content access account.
- SP_UserSync, user profile synchronization account.
- SP_EnterpriseAdmin, powerful account for handling all kinds of high privileg operations.
- Farm administrators, normal admin user accounts are used as SharePoint Farm Administrators.
