public IReadOnlyList<Item> LayerTemplatePackages {get;}

{
    //Gets the collection of layer template packages installed with Pro for use with maps
    var items = MapView.Active.Map.LayerTemplatePackages;
    //Iterate through the collection of items to add each Map Note to the active map
    foreach (var item in items)
    {
        //Create a parameter item for the map note
        var layer_params = new LayerCreationParams(item);
        layer_params.IsVisible = false;
        //Note: Needs QueuedTask to run
        //Create a feature layer for the map note
        var layerCreated = LayerFactory.Instance.CreateLayer<Layer>(layer_params, MapView.Active.Map);
    }
}