Brush presets: Filter by tool

Now that all of our brush-related tools have come together in one place, the new Brushes panel, there needs to be a way to search or filter the brushes by tool. For instance, there are only a few brushes for the Eraser tool, and it would be nice to be able to access them all at once. It would be immensely helpful if there were a dropdown from which you could select a tool, which would hide all brushes not associated with that tool (and all folders without a brush for that tool).