Sub Primer()
 ' True - пустой, False - не пустой
 For Each ws In ThisWorkbook.Sheets
   Debug.Print ws.Name, ws.UsedRange.Address( 0 ,  0 ) = "A1" And Range("A1") = ""
 Next ws
End Sub

Sub Primer2()
 ' True - пустой, False - не пустой
 For Each ws In ThisWorkbook.Sheets
   Debug.Print ws.Name, Evaluate("=sum(Len(" & ws.UsedRange.Address & "))") =  0 
 Next ws
End Sub

Sub Primer3()
 ' True - пустой, False - не пустой
 For Each ws In ThisWorkbook.Sheets
   Debug.Print ws.Name, ws.Cells.Find("*") Is Nothing
 Next ws
End Sub