Recommended React

• Apps
• https://github.com/devhubapp/devhub
• https://github.com/benawad/codeponder (with coding livestream!)
• https://github.com/cypress-io/cypress-realworld-app
• https://github.com/alan2207/bulletproof-react
• Design Systems/Component Libraries
• https://github.com/seek-oss/braid-design-system/ (see how to use TS to validate props)
• https://github.com/palantir/blueprint
• https://github.com/Shopify/polaris
• https://github.com/microsoft/fluentui
• Libraries
• https://github.com/formium/formik/
• https://github.com/jaredpalmer/react-fns
• Misc
• https://github.com/NullVoxPopuli/react-vs-ember/tree/master/testing/react
• https://github.com/artsy/reaction
• https://github.com/artsy/emission (React Native)
• @reach/ui's community typings
• https://github.com/pshrmn/curi/tree/master/packages/router

Older but still worth checking:

• https://bitbucket.org/atlassian/atlaskit-mk-2/src/master/
• https://github.com/contiamo/operational-ui

React Boilerplates:

• https://github.com/rwieruch/nextjs-firebase-authentication: Next.js + Firebase Starter: styled, tested, typed, and authenticated
• @jpavon/react-scripts-ts alternative react-scripts with all TypeScript features using ts-loader
• webpack config tool is a visual tool for creating webpack projects with React and TypeScript
• https://github.com/innFactory/create-react-app-material-typescript-redux ready to go template with Material-UI, routing and Redux

React Native Boilerplates: contributed by @spoeck

• https://github.com/GeekyAnts/react-native-seed
• https://github.com/lopezjurip/ReactNativeTS
• https://github.com/emin93/react-native-template-typescript
• https://github.com/Microsoft/TypeScript-React-Native-Starter

TS Library Codebases to study

• https://github.com/Azure/azure-sdk-for-js
• https://github.com/sindresorhus/is
• https://github.com/probot/probot
• https://github.com/intuit/auto
• https://github.com/polymer/tools
• https://github.com/nteract/nteract
• https://github.com/pgilad/leasot
• https://github.com/JasonEtco/actions-toolkit
• https://github.com/ferdaber/typescript-bootstrap/
• https://github.com/contiamo/operational-scripts
• https://github.com/nobrainr/morphism
• https://github.com/slackapi/node-slack-sdk