public Form1()
{
    InitializeComponent();

    var types = new List<Type> { typeof(Label), typeof(TextBox) };

    var message = new StringBuilder();

    foreach (Type type in types)
    {
        IEnumerable<Control> c = GetAllControls(this, type);
        message.AppendLine($"Totale '{type.Name}': {c.Count()}");
    }

    MessageBox.Show(message.ToString());
}

public IEnumerable<Control> GetAllControls(Control control, Type type)
{
    List<Control> controls = control.Controls.Cast<Control>().ToList();

    foreach (Control c in controls.SelectMany(ctrl => GetAllControls(ctrl, type))
        .Concat(controls))
    {
        if (c.GetType() == type) yield return c;
    }
}

    Dim types As List(Of Type) = New List(Of Type) From { GetType(Label), GetType(TextBox) }

foreach (Control c in controls.SelectMany(ctrl => GetAllControls(ctrl, type))
        .Concat(controls))
    {
        if (c.GetType() == type) yield return c;
    }

Private Function GetAllControls2(ByVal control As Control, ByVal type As Type) As List(Of Control)

    Dim controls(control.Controls.Count - 1) As Control
    control.Controls.CopyTo(controls, 0)

    Dim output As List(Of Control) = (From c In controls.SelectMany(Function(ctrl) GetAllControls(ctrl, type)).Concat(controls) Where c.GetType() = type).ToList()
        
    Return output

End Function

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    Dim types As List(Of Type) = New List(Of Type) From {GetType(Label), GetType(TextBox), GetType(CheckBox)}

    Dim message As StringBuilder = New StringBuilder()

    For Each type As Type In types

        Dim allControls As List(Of Control) = GetAllControls(Me, type)

        ' === Proprietà comuni e presenti nel Tipo Control, es. Name
        
        ' Ciclo tutte i controlli restituiti per il tipo corrente
        For Each control As Control In allControls

            Dim name = control.Name

        Next

        ' Leggo il nome del primo controllo della lista
        Dim nomePrimoControllo = allControls.FirstOrDefault().Name

        ' Salvo in una lista tutti i nomi dei controlli (method sintax)
        Dim nomiDiTuttiIControlli1 = allControls.Select(Function(textbox) textbox.Name)
        ' Salvo in una lista tutti i nomi dei controlli (query sintax)
        Dim nomiDiTuttiIControlli2 = From control In allControls Select control.Name

        ' Salvo in una lista tutti i nomi dei controlli visibili (method sintax)
        Dim nomiDiTuttiIControlliVisibili1 =  allControls.Where(Function(control) control.Visible).Select(Function(control) control.Name)
        ' Salvo in una lista tutti i nomi dei controlli visibili (query sintax)
        Dim nomiDiTuttiIControlliVisibili2 = From control In allControls Where control.Visible Select control.Name


        ' === Azioni specifiche per tipo

        If type = GetType(CheckBox) then

            Dim allCheckbox = allControls.Cast(Of CheckBox).ToList()

            ' Ciclo tutte le checkbox
            For Each checkbox As CheckBox In allCheckbox

                Dim checked = checkBox.Checked

            Next

        End If

        message.AppendLine("Totale '" + type.Name + "': " + allControls.Count.ToString())

    Next

    MessageBox.Show(message.ToString())

End Sub