Notepad++ - A free source code editor which supports several programming languages running under the MS Windows environment.
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.
Smultron - Smultron is an elegant and powerful text editor for macOS that is easy to use.
Stashany - Online notepad for developers
Sublime Text - Sublime Text is a sophisticated text editor for code, html and prose - any kind of text file. You'll love the slick user interface and extraordinary features. Fully customizable with macros, and syntax highlighting for most major languages.
Calmly Writer - Distraction-free text editor for Mac, Windows, Linux and ChromeOS.