bibisco - bibisco is a novel writing software.
Scribes - A text editor for GNOME that combines simplicity with power.
Manuskript - Open-source tool for writers.
Big Huge Labs Writer - Writer is a free online distraction free writing environment provided by Big Huge Labs.
WriteFreely - Write Freely is free and open source software for starting a minimalist, federated blog — or an entire community.
Caret - Better Markdown Editor for Mac / Windows / Linux