Typora - A minimal Markdown reading & writing app.

Todoist - Todoist is a to-do list that helps you get organized, at work and in life.

Dillinger - joemccann has 95 repositories available. Follow their code on GitHub.

Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.

StackEdit - Full-featured, open-source Markdown editor based on PageDown, the Markdown library used by Stack Overflow and the other Stack Exchange sites.

Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.