tex-upmethodology provides a complete set of LaTeX styles that permit you to write documents according to a UP-based methodology. Its major features are document history, task management, design and specification documentation, and helping tools. tex-upmethodology is officially supported by CTAN.
AutoLaTeX is a tool for managing small to large LaTeX documents. It detects which files which are used to build the document (included TeX files, BibTeX, figures, etc.), and launches the various different tools (latex, bibtex, makeindex) when the sources files have been changed. It provides translation rules which automatically generate figures in EPS, PNG, or PDF formats from different types of sources (dia, xfig, svg, astah, source code, etc.) AutoLaTeX also provides graphical user interfaces, a plugin for the editors Gedit and Sublime Text, and a standalone Gtk application.
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.
TeXcount is a Perl script for counting words in LaTeX documents. It parses valid LaTeX documents counting words, headers, formulae (mathematics), and floats/begin-end groups. To run the script, you can either download it and run it on your own computer, or you can use the Web interface. TeXcount is included in the CTAN TeX/LaTeX archive, and thus included in several TeX distributions. If you have TeX installed, chances are you may already have TeXcount.
TeX Live is an easy way to get up and running with TeX. It provides a comprehensive TeX system with binaries for most flavors of Unix, including GNU/Linux, and also Windows. It includes all the major TeX-related programs, macro packages, and fonts that are free software, including support for many languages around the world.
Asymptote is a powerful descriptive 2D and 3D vector graphics language for technical drawing, inspired by MetaPost but with an improved C++-like syntax. It provides for figures the same high-quality level of typesetting that LaTeX does for scientific text. Asymptote is a programming language as opposed to just a graphics program. It can exploit the best features of script (command-driven) and graphical user interface (GUI) methods. High-level graphics commands are implemented in the language itself, allowing them to be easily tailored to specific applications.
Kile is a user-friendly TeX/LaTeX editor for the KDE desktop environment. It lets you compile, convert, and view your document with one click and features auto-completion of (La)TeX commands, templates and wizards for starting a new document, easy insertion of many standard tags and symbols and the option to add user defined tags, inverse and forward search, collection of documents that belong together into a project, easy insertion of citations and references, a flexible build system, QuickPreview of selected parts of a document, easy access to various help sources, and advanced editing commands.