WriteNext - The writing application that boosts your writing. Increase focus and writing performance and reduce distractions by separating your creative writing from other activities. Let writing be the only activity you perform in the writing application.
Penflip - Typewrite is a real-time collaborative writing environment with Markdown support, versioning and Dropbox syncing. Alternatives to Penflip for Web, Windows, Mac, Linux, iPhone and more.
Calmly Writer - Distraction-free text editor for Mac, Windows, Linux and ChromeOS.
Cleartext - A text editor that allows only the 1,000 most common words
Stashany - Online notepad for developers
Quill - Powerful, API-driven rich text editor