Atom
Open source text editor from GitHub is “hackable to the core.” Supports themes for customized look and feel, plus modules can be added for various types of development work. Designed to be easy to learn.
Text editors
Brackets
Open source code editor for the web from Adobe still in the early stages, but with the promise of lots of development. Built with HTML, CSS and javascript. Easily extensible.
CotEditor
Text editor features syntax colouring for 26 languages, powerful find and replace including regular expressions, outline menu, split views, macros and keybindings.
Eddie
Ideal for C++/Obj-C development using makefiles and shell tools but can also be used with Xcode projects. Equally capable at editing HTML, JavaScript, Python, Ruby, Lua and many other languages.
Left
Distraction-free editor allows you to place markers in your text, which show up in a side panel. Comes with an inline thesaurus.
MacDown
Open source markdown editor for OS X, released under the MIT license, heavily influenced by Chen Luo’s Mou. Features highly customisable markdown rendering, syntax highlighting in fenced code blocks, sophisticated auto-completion.
Mini Diary
Mini Diary helps you make sense of all those thoughts churning in your mind every day. It doesn’t have a lot of features but it covers the basics: search, calendar, bold, italic, lists and word count. Plus it is password protected. Jump in and spill.
Noto
General-purpose text editor supports extensive encoding, multi-selection indentation, invisible characters and iCloud Drive integration.
SubEthaEdit
Collaborative coding for programmers has powerful editing tools, command line access and ability to create scripts. Now free and open source.
Sublime Text
Sophisticated text editor for code, markup and prose has a slick user interface and features goto anything, multiple selections, a command palette, distraction-free mode, split editing and instant project switch. A licence is required for continued use, but there is no time limit for evaluation.
TextWrangler
Bare Bones has updated TextWrangler and is making it free. It’s got a lot more features than BBEdit Lite, so why not go for it. But watch out — you may find yourself wanting to upgrade to the wonderful BBEdit.
Visual Studio Code
Open source, cross-platfrm text editor from Microsoft has thousands of extensions, IntelliSense completions and built-in support for Git.