ClassicMenu Indicator is a notification area applet (application indicator) for the top panel of Ubuntu's Unity desktop environment. It provides a simple way to get a classic GNOME-style application menu for those who prefer this over the Unity dash menu. Like the classic GNOME menu, it includes Wine games and applications if you have those installed.
jPDFNotes is a Java bean component which can be integrated into Java applications or deployed on the Web in an applet or using Java Web start. It allows users to mark up, review, and annotate PDF documents online. Most PDF annotations and features are supported, including graphical, sound, free text, typewriter, measurements (distance, perimeter, and area), file attachments, and bookmarks. All PDF fonts are supported (Types 0-3, OpenType, and TrueType).
OrgApp is a Java library to handle and draw organizational charts (organigrams). The library also has an applet and a Swing Java client able to view an organizational chart read from a file, in different formats (one of them based upon XML). The applet supports charts with different layouts and boxes with hyperlinks, customizable colors, sizes, positions, etc., and it is easy to embed it in an HTML page.
tmux-applets is a collection of tmux "applets" that are designed to be used in tmux's status bar. They are non-textual, using blocks of color instead. Currently, there are two applets provided. tmux-cpu-freq displays the CPU frequency level as colored blocks, and tmux-ping, which tries to ping a host and displays success or failure as a colored block.
Compa is a GNOME panel applet which can display the output of any system command on the panel. It can also display the output of a different command in its tooltip, and launch a different command when clicked. The text style can be modified using the Text Attribute Markup Language.