public static PaneCollection Panes {get;}

{
  List<uint> myPaneInstanceIDs = [];
  foreach (Pane p in FrameworkApplication.Panes)
  {
    if (p.ContentID == paneID)
    {
      myPaneInstanceIDs.Add(p.InstanceID); //InstanceID of your pane, could be multiple, so build the collection                    
    }
  }
  foreach (var instanceID in myPaneInstanceIDs) //close each of "your" panes.
  {
    FrameworkApplication.Panes.ClosePane(instanceID);
  }
}

{
  var mapPanes = FrameworkApplication.Panes.OfType<IMapPane>();
  foreach (Pane p in mapPanes.Cast<Pane>())
  {
    if (p.Caption == paneID)
    {
      p.Activate();
      break;
    }
  }
}

{
  string mapPaneCaption = "USNationalParks";
  IMapPane mapViewPane = FrameworkApplication.Panes.OfType<IMapPane>().FirstOrDefault((p) => p.Caption == mapPaneCaption);
  mapView = null;
  if (mapViewPane != null)
  {
    // activate the MapPane
    (mapViewPane as Pane).Activate();

    if (mapView != null)
    {
      // get the layers selected in the map's TOC
      var selectedLayers = mapView.GetSelectedLayers();
    }
  }
}

{
  // find all the table panes (table panes hosting map data)
  var tablePanes = FrameworkApplication.Panes.OfType<ITablePane>();
  var tablePane = tablePanes.FirstOrDefault(p => p is ITablePaneEx { Caption: "oldCaption" });
  if (tablePane is ITablePaneEx tablePaneEx)
    tablePaneEx.Caption = "newCaption";

  // find all the external table panes (table panes hosting external data)
  var externalPanes = FrameworkApplication.Panes.OfType<IExternalTablePane>();
  var externalTablePane = externalPanes.FirstOrDefault(p => p.Caption == "oldCaption");
  if (externalTablePane != null)
    externalTablePane.Caption = "newCaption";
}

{
  // find all the table panes (table panes hosting map data)
  var tablePanes = FrameworkApplication.Panes.OfType<ITablePane>();
  var tablePane = tablePanes.FirstOrDefault(p => p is ITablePaneEx { Caption: "caption" });
  if (tablePane is ITablePaneEx tablePaneEx)
    tableView = tablePaneEx.TableView;

  // if it's not found, maybe it's an external table pane
  if (tableView == null)
  {
    // find all the external table panes (table panes hosting external data)
    var externalPanes = FrameworkApplication.Panes.OfType<IExternalTablePane>();
    var externalTablePane = externalPanes.FirstOrDefault(p => p.Caption == "caption");
    if (externalTablePane != null)
      tableView = externalTablePane.TableView;
  }
}

{
  //Activate an already open layout view.
  //A layout view may be open but it may not be active.

  //Find the pane that references the layout and activate it. 
  //Note - there can be multiple panes referencing the same layout.
  foreach (var pane in ProApp.Panes)
  {
    var layoutPane = pane as ILayoutPane;
    if (layoutPane == null)  //if not a layout view, continue to the next pane
      continue;
    if (layoutPane.LayoutView.Layout == layout) //activate the view
    {
      (layoutPane as Pane).Activate();
      return;
    }
  }
}