Caret - Better Markdown Editor for Mac / Windows / Linux
Joplin - Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, tagged and modified either from the applications directly or from your own text editor.
Dillinger - joemccann has 95 repositories available. Follow their code on GitHub.
Boostnote - Boostnote is an open-source note-taking app.
Pine - A lightweight, modern macOS markdown editor written in Swift
Typora - A minimal Markdown reading & writing app.