Zenity - Zenity is a tool that allows you to display GTK dialog boxes in commandline and shell scripts.
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.
Yad - Yad (yet another dialog) is a fork of Zenity with many improvements, such as custom buttons...
Wolf Responsive Form Maker - Build mobile-friendly web forms with email notifications.
Glade - Glade is a RAD tool to enable quick & easy development of user interfaces for the GTK+ toolkit...
Webix Form Builder - Webix Form Builder tool is intended to speed up the process of form creating.