NotePlan - Make plans inside an individual markdown note for every day in your calendar. Use it as a journal for your daily tasks and plan todos in advance. For Mac, iPhone and iPad.
Whimsical Sticky Notes - Visual project management using sticky notes
Mochi - Write notes and flashcards with Markdown and study them with spaced repetition.
Jot - The no-fuss way to take notes
Markdown New Tab - Write notes in Markdown directly in the 'New Tab' page
Gone - An ephemeral to-do list