Overleaf - The online platform for scientific writing. Overleaf is free: start writing now with one click. No sign-up required. Great on your iPad.
Doxygen - Generate documentation from source code
TeXworks - The TeXworks project is an effort to build a simple TeX front-end program (working environment)...
Docsify.js - A magical documentation site generator.
Texmaker - Texmaker, free cross-platform latex editor
GitBook - Modern Publishing, Simply taking your books from ideas to finished, polished books.