Zenity - Zenity is a tool that allows you to display GTK dialog boxes in commandline and shell scripts.
Tiny Flashlight + LED - Tiny Flashlight + LED is free to use application that can be used anywhere else, having nicely built-in functionality.
Glade - Glade is a RAD tool to enable quick & easy development of user interfaces for the GTK+ toolkit...
Simple Flashlight - A clean flashlight with an extra bright display and customizable stroboscope.
Yad - Yad (yet another dialog) is a fork of Zenity with many improvements, such as custom buttons...
Task Killer - Task Killer is an application which automatically forces other applications to stop which are running in the background, making you enhance your smartphone performance and battery life.