MenuLibre is described as 'An advanced menu editor that provides modern features in a clean, easy-to-use interface. All without GNOME dependencies, so even lightweight systems can benefit from the sanity that MenuLibre offers'. There are six alternatives to MenuLibre for Linux, BSD, KDE and Solaris. The best alternative is AppEditor, which is both free and Open Source. Other great apps like MenuLibre are lxappearance (Free, Open Source), obmenu (Free, Open Source), KMenuEdit (Free, Open Source) and Alacarte (Free, Open Source).
LXAppearance is the standard theme switcher of LXDE. Users are able to change the theme, icons, and fonts used by applications easily. It also includes support for configuring openbox, via a plugin called lxappearance-obconf.
Alacarte is an easy-to-use menu editor for GNOME that can add and edit new entries and menus. It works with the freedesktop.org menu specification and should work with any desktop environment that uses the spec.