You can create your own Contact Forms on Makerble and add a List field to the form

Note: if you are adding a Category field to a Contact Form, you must create the Category field first.

Steps

Select My Apps in the top menu
Scroll to the right and select Contact Forms
You arrive on the Manage Contact Forms page
Click the New Contact Form button
Name your Contact Form
Start by choosing the type(s) of Contact that this form should be used to create (there are four types: Person, Organisation, Animal, and Object)
The right section called Your Contact Form displays the fields which are already in your Contact Form. (Every Contact Form has a set of default fields that are added automatically. Those that you can remove have an X symbol next to them.)
You can add existing fields to your Contact Form and/or create new fields to add to the Contact Form.
To add an existing Category Field
The red box contains the filters that determine which fields are available
Deselect the different fields until only Category is selected
The available fields box in the middle will update to only display the fields that are of the Category type and the Default type
The Category fields that your organisation has created are displayed in alphabetical order
Press the Add to form button to add a List field to your Contact Form
The fields that you add will appear on the right side.
Scroll to the bottom and press Save.
You arrive on the Manage Contact Forms page

Makerble User Guide