You can use tools like CleanMyMac to show folders and their sizes. All cache and library files are counted under System, e.g. files from vagrant, docker, vms, old jetbrains IDEs, caches from rarely used/uninstalled apps etc.
You don‘t need to buy the full version, you can just use the info and delete it manually in Finder.
You don‘t need to buy the full version, you can just use the info and delete it manually in Finder.