Beautiful.AI - AI-powered presentation tool that makes it fast and easy for anyone to build clean, modern and professionally designed slides.
Minimalist Markdown Editor - This is the simplest and slickest Markdown editor.
WebSlides - Easily create great-looking HTML presentations.
Markdown by DaringFireball - Text-to-HTML conversion tool/syntax for web writers, by John Gruber
Slidebean - Presentations that design themselves
Typora - A minimal Markdown reading & writing app.