KOffice is an integrated office suite based on the KDE libraries. KOffice currently includes KWord, KSpread, KPresenter, KChart, Karbon14, Krita, Kexi, KFormula, Kugar, and Kivio. There are no special mail and news clients included in KOffice, because there are KMail and KNode available for KDE anyway. All KOffice components work together, and you can embed every KOffice component into any other KOffice component. This is realized using the KParts object model.
Siag Office is a free office package which consists of the spreadsheet Siag, the word processor PW, the animation program Egon, the text editor XedPlus, the file manager Xfiler and the previewer Gvu. Siag is easy to use, yet infinitely flexible through multiple embedded interpreters and a plugin mechanism that allows other programs to run inside the main document. The supported interpreters are SIOD, Guile, Tcl, and Python.
Z-Doc is an Aportis(TM) DOC compatible reader/writer with support for encryption, compression, and serial port input/output. It is built mainly for programmers who wish to access the DOC format files from a Palm Pilot or from standalone Unix C code. It has modular read/write functions which can be picked up and dropped into other GPLed projects.
TeXtrace is a collection of scripts that convert any TeX font into a Type1 .pfb outline font immediately suitable for use with dvips, pdftex, Acroread, and many other programs. The main advantage of using Type1 fonts with TeX is that Acroread renders TeX's bitmap fonts ugly on screen, but it renders outline fonts beutifully and fast.
XMLmind XML Editor (XXE for short) is a full-fledged XML 1.0 editor, featuring a word processor-like view (CSS2 styled). It was designed to make technical persons comfortable with and productive at editing XML documents and XML data. It can be used with or without a CSS style sheet. If a CSS style sheet has been attached to the document, a word processor-like view may be used to edit the document; otherwise a tree view is used. A substantial subset of CSS2 is supported, including tables, counters, and generated content. It has a multi-level undo/redo, is written in Java, and should run on a large variety of platforms.