public IReadOnlyList<Element> GetElementsAsFlattenedList()

{
  //Note: Must be on QueuedTask.Run
  //Find elements by name
  var layoutElementsToFind = layout.FindElements(new List<string>() { "Point 1", "Line 3", "Text 1" });
  //Get the collection of elements from the page layout. Nesting within GroupElement is preserved.
  var elementCollection = layout.GetElements();
  //Get the collection of Element from the page layout as a flattened list. Nested groups within GroupElement are not preserved.
  var elements = layout.GetElementsAsFlattenedList();
  //Convert collection of the elements to a collection of GraphicElements.
  var graphicElements = elements.ToList().ConvertAll(x => (GraphicElement)x);
  //Find elements by type
  //Find all point graphics in the Layout
  var pointGraphics = graphicElements.Where(elem => elem.GetGraphic() is CIMPointGraphic);
  //Find all line graphics in the Graphics Layer
  var lineGraphics = graphicElements.Where(elem => elem.GetGraphic() is CIMLineGraphic);
  ////Find all polygon graphics in the Graphics Layer
  var polyGraphics = graphicElements.Where(elem => elem.GetGraphic() is CIMPolygonGraphic);
  ////Find all text graphics in the Graphics Layer
  var textGraphics = graphicElements.Where(elem => elem.GetGraphic() is CIMTextGraphic);
  ////Find all picture graphics in the Graphics Layer
  var pictureGraphic = graphicElements.Where(elem => elem.GetGraphic() is CIMPictureGraphic);
}