I have a Macbook Pro Retina 13" Mid 2014, with a 500GB disk.
I never have to work with large files such as movie editing or anything like that nor do I use time machine backups. After upgrading to Catalina 10.15.4 I noticed my disk shows ~200GB of used space which I have no idea where is it coming from.
Rebooting doesn't help and even the system information tool is not giving information on what's taking up that much space.
In the image below, the other sections (Applications, Documents, etc) all contain the correct sizes that I expect from the stuff that I use.