Markdown Edit is a very minimalist Markdown editor (CommonMark or GitHub-flavoured), with such a stripped-back interface (a few subdued icons top-right of the title bar) that it may take a moment before you even realise it's there.
And yet, there's surprising power here. Like DOCX and HTML import, for instance - just drag and drop and they'll open immediately, Markdown code on the left, live preview on the right.
Image handling is just as smart. Drag and drop a picture and Markdown Edit can immediately upload it to Imgur and insert the necessary links (there's also an option to use a local path, if you prefer).
You get plenty of the standard editing support tools: spell checking, a word count, auto save, Find and Replace with wildcards and regular expressions.
But there are more, too. Like a Snippets feature which expands text to help quickly insert common words and phrases. And may be customised with various parameters, so that you can also embed things like the contents of the clipboard.
There's also smart syntax highlighting, a vast number of configuration options, and it's all speedily controlled via a well-chosen set of keyboard shortcuts.
Version 1.32 changes:
make about label style wider
fix crash on tab at start of doc
crash report fixes
An excellent Markdown editor which doesn't get in your way, yet has plenty of functionality available if you need it.