I'm assuming your asking mainly about the preset manager, and the product select list?
Themes are For CSS Menu writer - Menu Themes. in other words, the menu design.
CSS From Builder - Form Designs are the CSS Look of the form. When you save a form design Preset, in form builder, the design will become available in the Design Preset list of the Data Assist create Pages wizard.
Data Bridge - Preset are the preset application types that are available, the define the table used, the pages that will be created, and the other application settings you can configure in the Data Bridge create pages wizard.
The preset manager groups the preset types in to the products they apply to.
the naming convention you use when creating presets is up to you.