MetaDirectory
- FOX GUI Toolkit
An open source cross-platform C++ based Toolkit for GUI development.
- GUIS
Open source widget server. (Python, Ruby, GTK2) [OS Independent]
- InputGUIDO
A GUI being developed for older DOS systems that are incapable of running Windows.
- Java Gui Builder
An engine that reads XML files describing graphical user interfaces layout.
- KronoJunior
Open source GUI for less powerful or old computers.
- ObjectCentral - V
A free, multiple platform C++ graphical user interface framework.
- The Official FVWM Homepage
The standard window manager for linux, stable but not as pretty as Window Maker or Enlightenment.
- Prima
Toolkit for multi-platform GUI development. (Perl) [OS Independent]
- Tango Desktop Project
Aims to create a consistent graphical user interface experience for free and Open Source software. Style guidelines, basic icon library, and list of projects using tango icons.
- The Visual Component Framework
C++ framework created to provide platform GUI framework, features such as Java and Java's Swing, and Borland's Visual Component Library.