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.
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.
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.
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.
MpFot allows you to create MetaPost files from images in JPEG or GIF format. It uses Java2 and can optionally process the images before rendering to MetaPost files. MpFot can currently modify brilliance, color balance, and saturation, and it can also perform posterization, inversion of colors, and manual cropping. All the changes can be compared with the original image through a courtain-like facility.
dlh is a fast LaTeX-to-HTML translator written in C that can handle most of LaTeX. It features not invoking LaTeX for any purpose; with the exception of figure support it's completely independent of any other program. In particular, it generates all cross-references and table of contents in a single run Tables are supported and translated into HTML3 tables, and PostScript figures (\psfig command) are supported (requires GhostScript and pnmtogif to translate PS into GIF files).