If you want to do cool things in web browsers (Front End), learn Javascript (AKA ECMAscript 'officially')... which truly is the most popular and ubiquitous programming language the Earth has ever produced to date. Likely you'll want to bookmark MDN by the way.

If you are concerned about writing backend Web stuff, PHP is proven (php.net is dope) and works seamlessly with Apache and other web servers. If you're into full stack web development, Laravel throws a full frontend framework on top of PHP with Vue.js javascript sparkles. Also, if you haven't used PHP with MySQL (or MariaDB) then you really haven't touched the true power of PHP, so go bone up on how to leverage databases with phpMyAdmin.

If you want to write command line scripts, drop into bash, python (be careful v3 is not backward compatible with still ubiquitous v2), or perl.

If you want to write something completely dependent on Oracle not being a dick, write it in Java, and god forbid you venture into the mind numbing jumble of conflicting I/O sub frameworks and other pointlessly confusing support libraries the Java community doesn't seem to be able to converge down to common core that everyone can agree on. In my mind Java is the new legacy COBOL for business majors because you have to use it increasingly due to some legacy decision you didn't make, not because anyone wants to write in Java. Indeed, even Google is moving away from Java for future versions of Android.

Then there is node.js - um Javascript completely reimagined to run on the backend. Lately lots of frontend javascript enahncement tools seem to have popped up as part of easy to install node packages.