I second Daisy Disk. When I made the leap from Windows to mac in the early 00s I wanted something to replace the freeware “scanner” I had found so entirely useful.
What’s the advantage of Daisy Disk over the built-in “About this Mac -> Storage -> Manage”? Always interested in lovely boutique MacOS software, but in this case the website doesn’t sell it well as an alternative to what’s already available.