In the most recent React applications that I’ve led development of, we built our component library in Storybook. It’s a great tool for documentation, testing, and discovery of components. Some interesting tidbits:

• Integrated Chromatic for automated visual regression tests
• Automated CI/CD built the library, ran tests, and exported it as a GitHub package which could then be imported by our applications
• The library also exposed our custom theme so that one-off components created in React apps could import and use things like colors and border radius, keeping the entire app consistent