Pure Writer - fast, smooth, fluid, at any time, never lose content, Markdown, super reliable

EssentialPIM - EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.

YourQuote - YourQuote is an interactive mobile app that helps you to write stories, quotes, screenplays, poems, and books.

Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.

Novelist - A portable writing assistant for novelists.

Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.