LINKDING

This one may get a longer writeup from me in the future, but I'm excited enough to point it out now. I love TextExpander (dearly), but for coding, TeaCode offers a basic feature set that's really useful in editors like Sublime, Code, and Xcode. You can include variables in an expansion and have them automatically filled in and transformed in the output. Works in any editor.

I'm playing with this right now. It allows you to save snippets with cells set to various types (text, markdown, code w/language), and stores them as JSON objects in text files. Thus, you can mix Markdown and code snippets, copy them out, tag them, and even has a presentation mode. It has a few missing features, but shows promise.