Macro to extract unique values from a range and deposit them in another column

I think this will do it.

Note that it expects a heading in column G as per your sample workbook.

Sub CollateAndExtractUniqueIDs()

Dim lColumns As Long: lColumns = Cells(1, Columns.Count).End(xlToLeft).Offset(0, -1).Column
Dim lNextRow As Long: lNextRow = 2
Dim lLastRow As Long

Application.ScreenUpdating = False
For i = 1 To lColumns
    lLastRow = Cells(Rows.Count, i).End(xlUp).Row
    Range(Cells(2, i), Cells(lLastRow, i)).Copy _
        Cells(lNextRow, lColumns + 1)
    lNextRow = lNextRow + (lLastRow - 1)
Next 'i

Range(Cells(1, lColumns + 1), Cells(lNextRow - 1, lColumns + 1)).AdvancedFilter _
    Action:=xlFilterCopy, _
    CopyToRange:=Cells(1, lColumns + 2), _
    Unique:=True

Application.ScreenUpdating = True
Application.ScreenUpdating = False

Cells(1, lColumns + 1).Value = "Combined"
Cells(1, lColumns + 2).Value = "Unique"

Application.ScreenUpdating = True
End Sub

Regards