Quiver - Quiver is a notebook built for programmers.
Zeal - Zeal is an API Documentation Browser.
Code Bank - Code Bank is a code snippet manager with support for a local database as well as a shared database.
DevDocs - Open source API documentation browser with instant fuzzy search, offline mode, keyboard shortcuts, and more
GitHub Gist - Gist is a simple way to share snippets and pastes with others.
Snippely - Snippely is a basic text and code organizational tool.