I like some of the new features in iOS 12 like shortcuts, memoji and possibly group facetime chat could be helpful.
The Mojave looks pretty sweet, I like the dark theme. Beats seeing a white background on my mac. The editing of pics, spreadsheets will be helpful and the new protection security will even great.
The watch OS has some nice features like the interactive notifications and the walkie-talkie, but you need 2nd watch user.
The tvOS update mainly for Apple 4K users, which I don't have one yet.