I've used a fair few of those, but don't know what SAS and Apex are. I've heard people rave about Ruby and Rust so it might be fun to look at those. I quite like to have a course to follow and I do have access to some via work. It's just a matter of having the time. I've been doing some music courses lately as I spend enough time coding for work, which is all Python. There are plenty of areas I have not explored, but I may have to wait for retirement (not too far away) to play with those. A friend who retired recently is into microcontrollers, but he plays around with all sorts of weird stuff. It's always good to have a project with some goals to motivate you.
!BEER
SAS is math so not for me ;) Apex is for salesforce so I might have done some without knowing!