Learn for free in 2023:

1. Git & GitHub
LearnGitBranching.js.org

2. HTML and CSS
LearnHTMLCSS.online

3. Python
PythonTutorial.net

4. React
React-tutorial.app

5. DS, Algo
Visualgo.net/en

6. JavaScript
Learn-JS.org

7. SQL
SQLbolt.com