AbiWord - AbiWord is a free software word processor.
Overleaf - The online platform for scientific writing. Overleaf is free: start writing now with one click. No sign-up required. Great on your iPad.
LibreOffice - Writer - Open-source cross-platform word processor.
TeXworks - The TeXworks project is an effort to build a simple TeX front-end program (working environment)...
Zoho Writer - Create. Review. Distribute
TeXstudio - TeXstudio is an integrated environment for writing LaTeX documents.