In WAB, it would be useful to have a search/filter option in the LayerList widget that filters, or selects and scrolls, to the various layers that meet a user inputted text value. This would be similar to the search functionality in the Contents pane in ArcGIS Pro. This would be especially valuable when your web map has a lot of layers, as it can be time consuming to scroll through the layer list and drill into the sublayers of services to find a layer of interest.
