Zenity - Zenity is a tool that allows you to display GTK dialog boxes in commandline and shell scripts.
Wolf Responsive Form Maker - Build mobile-friendly web forms with email notifications.
Yad - Yad (yet another dialog) is a fork of Zenity with many improvements, such as custom buttons...
AbcSubmit - Create forms with ease using our form creator software. Add and personalize form fields according to your individual needs. Generate custom reports to view and analyze all your form submissions.
Glade - Glade is a RAD tool to enable quick & easy development of user interfaces for the GTK+ toolkit...
Touchbase - Contact Form Builder - Build beautiful contact forms, feedback forms, registration forms and surveys for your website.