Caret - Better Markdown Editor for Mac / Windows / Linux
Markdown by DaringFireball - Text-to-HTML conversion tool/syntax for web writers, by John Gruber
Dillinger - joemccann has 95 repositories available. Follow their code on GitHub.
Typora - A minimal Markdown reading & writing app.
Pine - A lightweight, modern macOS markdown editor written in Swift
StackEdit - Full-featured, open-source Markdown editor based on PageDown, the Markdown library used by Stack Overflow and the other Stack Exchange sites.