MacDown - MacDown is an open source Markdown editor for OS X, released under the MIT License.
Markdown Viewer - Markdown document viewer. Allows to visualize formatted markdown documents in browser.
Frost - An open API for Blockchain timestamping
Markdown Preview for (Neo)vim - Preview markdown on your modern browser with synchronized scrolling and flexible configuration.
Typora - A minimal Markdown reading & writing app.
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.