Lots of people use React as the V in MVC. Since React makes no assumptions about the rest of your technology stack, it's easy to try it out on a small feature in an existing project.
Polymer is a new type of library for the web, designed to leverage the existing browser infrastructure to provide the encapsulation and extendability currently only available in JS libraries. Polymer is based on a set of future technologies, including Shadow DOM, Custom Elements and Model Driven Views. Currently these technologies are implemented as polyfills or shims, but as browsers adopt these features natively, the platform code that drives Polymer evacipates, leaving only the value-adds.
React Router is a complete routing solution designed specifically for React.js. It painlessly synchronizes the components of your application with the URL, with first-class support for nesting, transitions, and server side rendering.
Visual primitives for the component age. Use the best bits of ES6 and CSS to style your apps without stress 💅
A command-line interface tool that you use to initialize, develop, scaffold, and maintain Angular applications. You can use the tool directly in a command shell, or indirectly through an interactive UI such as Angular Console.