go to terminal and do an “apt-get update” and then a “sudo synaptic”
It’s a package manager that let’s you install all kinds of stuff. Some of these once installed will appear in the GUI menu, others will just drop themselves in seemingly random places in the filesystem. Anyway, it’s at least good to see what’s out there.
Terminal is tricky at first, but if you ever need a good explanation on how to use a particular command, just type “man” space and the command. It’s short for manual and will walk you through the syntax and options.
Ubuntu is a good place to start. Good luck!