SoChat - Chat with everyone
Typora - A minimal Markdown reading & writing app.
chitchat - Chat Room with Selfies and Pagers (yes, pagers!)
Dillinger - joemccann has 95 repositories available. Follow their code on GitHub.
Ablo - Say hello to the world
StackEdit - Full-featured, open-source Markdown editor based on PageDown, the Markdown library used by Stack Overflow and the other Stack Exchange sites.