The Custom Customer Field Display module allows you to display custom customer fields on the store side and not just the admin. In addition, you can make the fields required or not.
Learn about Custom Customer Field Display

The Category Assignment Manager module gives you quick and easy access to assigning categories to your products and child categories to your parent categories.
Learn about Category Assignment Manager

This import utility allows you to delete mass amounts of products via a flat file upload.
Learn about Product Delete Import

This import export utility allows you to import and export your attribute templates.
Learn about Attribute Template Import Export

This import export utility allows you to easily import and export your related product associations via flat file.
Learn about Related Product Import & Export