Very nice Tutorials, Examples, and Overviews of PHP, HTML, CSS, MySQL, plus tons of free books to read and learn:

1) Goalkicker:
PHP:https://books.goalkicker.com/PHPBook/
Others:https://books.goalkicker.com/

2) DevTut
PHP:https://devtut.github.io/php/
Others:https://devtut.github.io/

3) William Durand presentations
PHP:http://edu.williamdurand.fr/php-slides/#slide1
PHP Extended:http://edu.williamdurand.fr/php-slides/extended.html
Git, GitHub & Open Source:https://slides.williamdurand.fr/git-and-github-and-open-source/#/
Docker:https://slides.williamdurand.fr/deploying-with-docker/#/
From STUPID to SOLID Code!:https://williamdurand.fr/2013/07/30/from-stupid-to-solid-code/
Rapid Application Development & Deployment:https://slides.williamdurand.fr/rapid-app-development-and-deployment/

4) 50 Free eBooks for Web Designers & Developers
https://speckyboy.com/free-web-design-ebooks/

5) Tons of FREE books from Springer (incl. machine learning, AI, data analysis, and statistics with R):
https://github.com/BaseMax/FreeSpringerBook

So much to learn, so little time!!!!

Too much stuff
thanks for this Mamba