Typora - A minimal Markdown reading & writing app.
Hellosaurus - Interactive mobile shows kids can play, not just watch
Dillinger - joemccann has 95 repositories available. Follow their code on GitHub.
Hullabalu - Interactive stories for kids
StackEdit - Full-featured, open-source Markdown editor based on PageDown, the Markdown library used by Stack Overflow and the other Stack Exchange sites.
Tellast - Write stories collaboratively with others