Draftsend - Presentations you can 👀 and 👂
Minimalist Markdown Editor - This is the simplest and slickest Markdown editor.
Slidebean - Presentations that design themselves
Typora - A minimal Markdown reading & writing app.
Slides - Slides is a place for creating, presenting and sharing presentations. The Slides editor is available right in your browser. Unlike traditional presentation software, like PowerPoint, there's no need to download anything.
Markdown by DaringFireball - Text-to-HTML conversion tool/syntax for web writers, by John Gruber