Ask HN: Your favourite React plugins/components?

Currently I make good use of:

* React Bootstrap (https://react-bootstrap.github.io/introduction.html) - allows use of ready-to-go Bootstrap components such as tabs without having to deal with any of the JQuery initialisation normally required, and makes them feel like first-class citizens in React.

* tcomb-form (https://gcanti.github.io/tcomb-form/) - allows you to quickly build forms that can validate themselves with set client side rules, and server responses using a simple object.

Are there any other great React plugins/components/tools etc. that make developing a React project easier?