Typora - A minimal Markdown reading & writing app.
Hemingway - Hemingway App makes your writing bold and clear.
StackEdit - Full-featured, open-source Markdown editor based on PageDown, the Markdown library used by Stack Overflow and the other Stack Exchange sites.
Write App - No-distraction writing tool for your productivity.
MarkText.app - Mark Text is a Markdown editor for Mac, Windows and Linux.
ProWritingAid - For the smarter writer. A grammar checker, style editor, and writing mentor in one package.