I am seeing this. I have been running a lot of Node.js data processing scripts to generate data on an external hard drive. I am logging a lot of stuff to the terminal windows that are running those processes. I am pretty sure there aren't any memory leaks in these (albeit hacked together) scripts. So I'm wondering what I can look at or which commands I can run to get a more fine-grained picture of what on my "System" is taking up space, so I can clear it out and make some more room on my MacBook hard drive.
At first you can navigate to Apple logo (top-left) in taskbar -> Storage tab --> manage and get an overview of what your system has allocated.
From terminal you can use the du command
du -sh ~ du -sh *
Try Disk Invetory X too.
hope this helps