Not sure where to look first? Here are some interesting repositories:
metafizzy/zdog, facebook/create-react-app, reactjs/redux, mzabriskie/react-draggable, deepmind/alphafold, pmndrs/react-spring, the-pudding/data, animate-css/animate.css, joshwcomeau/react-flip-move, d3/d3-geo, paperjs/paper.js, popperjs/popper-core, marmelab/react-admin, vuejs/vue, gcanti/fp-ts, ant-design/ant-design, jaredpalmer/razzle