Penflip - Typewrite is a real-time collaborative writing environment with Markdown support, versioning and Dropbox syncing. Alternatives to Penflip for Web, Windows, Mac, Linux, iPhone and more.
Tree - Write documents in tree-like organisation with Markdown
Pine - A lightweight, modern macOS markdown editor written in Swift
Markdown New Tab - Write notes in Markdown directly in the 'New Tab' page
EME - Elegant Markdown editor
TabNotes - Markdown notepad in your new tab