OmniDiskSweeper is now at version 1.11. It now supports macOS 10.14 Mojave. It requires at least macOS 10.13 High Sierra. Older versions are available at the OmniGroup site.
"Version 1.11 — Sunday, September 23, 2018
• Dark Mode — Added support for Mojave’s Dark Mode.
• File Access Alerts — On Mojave, any app which attempts to access a folder which contains your calendars, contacts, photo library, or reminders will trigger an alert. When OmniDiskSweeper scans the files in your home folder, it triggers these alerts: so we’ve added a description that explains that OmniDiskSweeper doesn’t actually open any of the files it scans, it just lists those files for you to review. If you wish, you can avoid these prompts by granting OmniDiskSweeper full disk access under System Preferences > Security & Privacy > Privacy. (Or you can proceed without granting OmniDiskSweeper permission to scan those folders, in which case OmniDiskSweeper won’t be able to tell you how large they are.)"
Provided kindly for free, this is a reasonable, colorful, useful way to dig around on your drives to find what's taking up all your drive space and how much of it, starting with the invisible files and folders we normally don't see.
Also note that the free OmniWeb browser is still around and kept up-to-date. I've been using their test versions for years and still prefer it for some purposes on the net.
[Sad note: OmniDictionary, abandoned by OmniGroup years ago, has finally flown off to code heaven as of macOS 10.14. Mojave. It's an eternal bomber. I'll miss the good old thing.]