GNU Aspell is a spell checker designed to eventually replace Ispell. It can either be used as a library or as an independent spell checker. Its main feature is that it does a superior job of suggesting possible replacements for a misspelled word than just about any other spell checker out there for the English language. Unlike Ispell, Aspell can also easily check documents in UTF-8 without having to use a special dictionary. Aspell will also do its best to respect the current locale setting. Other advantages over Ispell include support for using multiple dictionaries at once and intelligently handling personal dictionaries when more than one Aspell process is open at once.
GNU TeXmacs is a free wysiwyw (what you see is what you want) editing platform with special features for scientists. The software aims to provide a unified and user friendly framework for editing structured documents with different types of content: text, mathematics, graphics, interactive content. TeXmacs can also be used as an interface to many external systems for computer algebra, numerical analysis, and statistics. New presentation styles can be written by the user and new features can be added to the editor using Scheme.
KBabel is a set of tools for editing and managing PO files created by gettext. Its main component is a powerful and comfortable PO file editor which features full navigation capabilities, full editing functionality, the ability to search for translations in different dictionaries, spell and syntax checking, showing diffs, and much more. It also includes a "Catalog Manager", which is a file manager view that provides an overview of PO files. Last but not least, it includes a standalone dictionary application which provides the additional capability of accessing KBabel's powerful dictionaries.
KDevelop is an integrated development environment which makes the creation and development of applications an easy task even for beginners. Highlights of the current release are: an application wizard for easy creation of KDE 4, Qt4, GNOME, and terminal C/C++ projects, full project management, a syntax-highlighting editor, code completion, an integrated dialog editor for the Qt/KDE GUI libraries, an internal debugger, a full-featured class browser with class tools, CVS and SVN support, an integrated HTML-based help system offering manuals and class-references, and extensive search mechanisms to browse sources and documentation.
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.
LE has many block operations with stream and rectangular blocks, can edit both unix and dos style files (LF/CRLF), is binary clean, has hex mode, can edit text with multi-byte character encoding, has full undo/redo, can edit files and mmap-able devices in mmap shared mode (only replace), has tunable syntax highlighting, tunable color scheme (can use default colors), tunable key map. It is slightly similar to Norton Editor, but has more features.
LyX is a document processor that encourages an approach to writing based on the structure of your documents, not their appearance. It is intended for people people who write and want their writing to look great without tinkering with formatting details, font attributes, or page boundaries. On screen, it looks like any word processor, but it uses the TeX engine for printed output and producing richly cross-referenced PDFs. It is stable and fully featured.
Motor is a text-mode integrated programming environment for Linux. It consists of an editor with syntax highlighting, a project manager, a makefile generator, gcc, ctags, gdb, autoconf/automake and grep front-ends. CVS integration is also provided. It allows one to edit, compile, and debug programs without a need to leave the IDE, automatically check in/out files from a CVS repository and import projects into CVS, and generate distribution packages (tar.gz and RPM). The color schemes are customisable.