Tetrisly - Starter kit for design systems and wireframes builder (Sketch/Figma)
React Rainbow Components - Build your web application in a snap.
Material Design Icons - 750 Free open-source glyphs by Google
Recharts - Redefined chart library built with React and D3
NativeBase - Experience the awesomeness of React Native without the pain
Material UI - A CSS Framework and a Set of React Components that Implement Google's Material Design