Notepad++ - A free source code editor which supports several programming languages running under the MS Windows environment.
Notepad3 - Notepad3 is a fast and light-weight Scintilla-based text editor with syntax highlighting.
Alternate TextBrowser - Easy to browse through text-files and also allows you to edit them.
TexEdit - TexEdit is a simple text editor developed by One Code Inc for the windows , Mac and Linux platforms. TexEdit offers a simple UI that makes it easier to navigate and use.
TED Notepad - TED Notepad is a portable text editor software that deals with a large variety of text processing tools, supplemental text clipboards, high accessibility through hotkeys, and a customizable number of settings and options.
QOwnNotes - QOwnNotes is a free plain-text notepad with markdown support for Linux, Mac OS X and Windows, that works together with ownCloud Notes.