Are you planning to learn React in 2021? Here are some free courses for you

Course on Scrimba

You'll learn key React features while building two apps and practice what you learn through interactive coding challenges and exercises along the way.

https://scrimba.com/learn/learnreact

Course on Codecademy

You’ll develop a strong understanding of React’s most essential concepts: JSX, class and function components, props, state, lifecycle methods, and hooks. And able to combine these ideas in React’s modular programming style

https://www.codecademy.com/learn/react-101 

Course on EggHead

The Beginner's Guide to React

https://egghead.io/courses/the-beginner-s-guide-to-react

Course on PluralSight

This is a beginner-level course and by the end, you should be comfortable working with function and class components in React, manage an application state, and be able to build simple React applications from scratch.

https://www.pluralsight.com/courses/react-js-getting-started

Course on Freecodecamp

- React in 10 hours. Its a YouTube video.