Atomize by Quarkly - Library for creating atomic react components
Anima App - Design, get feedback, convert to code, publish, iterate.
Ant Design - An enterprise-class UI design language and React implementation with a set of high-quality React components, one of best React UI library for enterprises
Timeline for Sketch - Create beautiful timeline animations in Sketch
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.
Invision - Prototyping and collaboration for design teams