Bulma - Bulma is an open source CSS framework based on Flexbox and built with Sass. It's 100% responsive, fully modular, and available for free.
Pixi.js - Fast lightweight 2D library that works across all devices
Phonebot - Make phone calls from within a Slack channel
Anime.js - Lightweight JavaScript animation library
Milligram - A minimalist CSS framework
Glottologist - JavaScript translation framework