Поиск совпадений в столбцах DataGridView

Public Class Form1
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        'организация данных для теста
        Dim vv(,) As String = {{"1", "6", "2"}, {"2", "5", "7"}, {"3", "1", "3"}, {"4", "3", "1"}, {"5", "", "5"}, {"", "", "4"}}
        DataGridView1.Rows.Add(6)
        DataGridView1.AllowUserToAddRows = False
        For i = 0 To vv.GetLength(0) - 1
            For j = 0 To vv.GetLength(1) - 1
                DataGridView1.Rows(i).Cells(j).Value = vv(i, j)
            Next
        Next
    End Sub
 
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        ListBox1.DataSource = Nothing
        Dim lst As New List(Of String)
        For i = 0 To DataGridView1.Rows.Count - 1
            For j = 0 To DataGridView1.Columns.Count - 1
                lst.Add(DataGridView1.Rows(i).Cells(j).Value)
            Next
        Next
        Dim ss As New List(Of String)
        For Each v As String In lst
            If v.Length > 0 Then
                Dim dd = lst.FindAll(Function(x) x = v)
                If dd.Count > 2 Then
                    ss.Add(v)
                End If
            End If
        Next
        ListBox1.DataSource = ss.Distinct.ToArray
    End Sub
End Class

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim Lst1 As New List(Of String)
        For i1 = 0 To DGV1.Rows.Count - 1
            Lst1.Add(DGV1.Rows(i1).Cells(0).Value)
            Lst1.Add(DGV1.Rows(i1).Cells(1).Value)
            Lst1.Add(DGV1.Rows(i1).Cells(2).Value)
        Next
        Dim suors1 = Lst1.ToArray
        Dim query = From item In suors1
                    Group By item Into Count()
        For Each result In query
            If result.Count > 2 Then
                LSTB1.Items.Add(result.item)
            End If
        Next
    End Sub

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim Lst1 As New List(Of String)
        For i1 = 0 To DGV1.Rows.Count - 1
            Lst1.Add(DGV1.Rows(i1).Cells(0).Value)
            Lst1.Add(DGV1.Rows(i1).Cells(1).Value)
            Lst1.Add(DGV1.Rows(i1).Cells(2).Value)
        Next
        Dim query = From item In Lst1
                    Group By item Into Count()
        For Each result In query
            If result.Count > 2 Then
                LSTB1.Items.Add(result.item)
            End If
        Next
    End Sub