Change references as required.
It does not use Sheet1 and it enters the info in Columns B, C and D in Sheet1
If you have a lot of sheets/data it will probably be slow.
Sub Get_All_Fonts()
    Dim i As Long, c As Range, sh1 As Worksheet
    Set sh1 = Sheets("Sheet1")
    Application.ScreenUpdating = False
    sh1.Range("D1").Value = sh1.Range("D1").Font.Name
    For i = 2 To ActiveWorkbook.Sheets.Count
        With Sheets(i)
            For Each c In .Range("A1").CurrentRegion
                If Application.WorksheetFunction.CountIf(sh1.Range("D1:D" & sh1.Cells(Rows.Count, 4).End(xlUp).Row), c.Font.Name) = 0 Then
                    sh1.Cells(Rows.Count, 4).End(xlUp).Offset(1, -2).Value = Sheets(i).Name
                    sh1.Cells(Rows.Count, 4).End(xlUp).Offset(1, -1).Value = c.Address
                    sh1.Cells(Rows.Count, 4).End(xlUp).Offset(1).Value = c.Font.Name
                End If
            Next c
        End With
    Next i
    Application.ScreenUpdating = True
End Sub