In frontend web normally Angular. In frontend mobile kotlin Android ir Ionic Backend with Php using Symfony or Slim

All of the above.

Additionally, back when I worked with Pick databases, I was able to make PickBASIC serve & request HTTP by opening sockets and speaking HTTP in the code myself. I used this to "modernize" some legacy applications.

I'm currently porting an open source project of mine from node.js to Go for better performance.

I have used JS, TS, ReasonML, CoffeeScript, ASP/C#, PHP, Java, Delphi, C, Rust and probably more which I don't remember to create web applications. I wouldn't say that I used all of them to the same degree and sometimes it was more toying around (like with ReasonML, which is great but lacking tooling), however it is also very interesting to see how they differ and when to use what.

All of them, but that's not an option... Django (Python) and Rust too.