Markdown by DaringFireball - Text-to-HTML conversion tool/syntax for web writers, by John Gruber

Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.

Characters - Characters makes it easy for writers, designers and developers to access special characters. They are easily found and copied to your clipboard, either as html code or as the character itself.

Synonymful - Improve your vocabulary and communicate like a pro.

Qwik - The HTML-first framework. Initialize apps of any size with < 1kb JS

Fluent - Fluent is a people-based marketing platform that uses real-time, one-to-one interaction to create custom audiences and serve personalized ads that drive performance at scale.