To simplify the catalog, and per your request, we categorized the gadgeteer modules.
http://www.ghielectronics.com/catalog/category/275/
There is no menu in the catalog where you can click “sensor” but the word “sensor” is hyper linked to the category. Click on it to see sensors only. We will be adding something to the menu in future. Here is an example http://www.ghielectronics.com/catalog/category/506/
We hope you like how they are organized. We tried to keep it generic so we do not need to add menus in future.