The web is full of information about MySQL. It is in fact the most widely used database on the Internet.
One of the best sources of information is the official website at www.mysql.com
Many free or low-cost applications use MySQL as their database. You can find a list at:
https://www.hotscripts.com/PHP/Scripts_and_Programs/index.html
You can also install more than 300 applications for every type of activity directly from your control panel under the Softaculous section. 99% of these applications use MySQL as their database.