We may sometimes require to reset the list item ID, for example to the number "1" or the library in SharePoint, then you can use PowerShell and access the WSS_Content database to the required lists or library, for this we need to know the GUID list or library through SharePoint Designer.
Please note that this script should not be run on Production servers. This is just for testing on pre testing environement. 

#Load System.Reflection.Assembly: SQL Server: System.Data[System.Reflection.Assembly]::LoadWithPartialName("System.Data")#SQL server name, Database and WSS_Content $conn = New-Object "System.Data.SqlClient.SqlConnection" -ArgumentList "server=SQLSERVER-01; database=USERLOCAL; integrated security=SSPI"$conn.Open()$cmd = $conn.CreateCommand()$cmd.CommandText = "UPDATE WSS_Content.dbo.AllListsAux set NextAvailableId=1 where ListID='D4D2CF11-1F16-4122-BA50-05A6A9CFD27E'"$cmd.ExecuteNonQuery()