Markdown by DaringFireball - Text-to-HTML conversion tool/syntax for web writers, by John Gruber
Video Speed Controller - Speed up, slow down, advance and rewind any HTML5 video with quick shortcuts.
Typora - A minimal Markdown reading & writing app.
Jump Cutter - Office & Productivity
StackEdit - Full-featured, open-source Markdown editor based on PageDown, the Markdown library used by Stack Overflow and the other Stack Exchange sites.
Saima - AI-based browser extension for personalized adaptive video speed.