For me its based on my SM role experience and types of roles available for the Devs Ive worked with. I'm learning TypeScript for React Apps as it's compatible with Office365 sites like SharePoint and Teams.
NodeJS is great client for task used to be handled by CMD-batch files, and it is supported for every OS.
and Java can handle the UI I need.
C# is for "solid programming" of heavy tasks (although I migrate most of it to NodeJS).
and when ever possible I 'delegate' tasks to an already known shell-commands or known programs instead of re-implementing it.
I favor chrome-extensions programming for solving pin-point web-related tasks.
And there are always scripting in/for AutoHotKey.
I put most of my scripts/programs in GitHub under "unlicensed" license, which mean public domain since I strongly believe in sharing and benefiting others.
Mine is the HTML, CSS, PHP and SQL bundle. I love being able to create a system or applet and see how things are going to look and build backwards to the function. I created an entire ergonomics platform with bootstrap and a bunch of custom css so style things out how I needed them to be, then started adding in PHP and SQL to add in the functionality and ecosystem I was looking to build.