Back in May of this year, Google Search Console added a feature to combine properties into sets so that you can see a snapshot of your Search Analytics reports for all your canonical versions of your sites.
It allowed you to combine HTTP, HTTPS, WWW, non-WWW, your mobile app or even completely different URLS, into one Search Analytics report. The issue was, there was only really one valuable report for property sets, it was the Search Analytics report.
Google announced today that you can now see many more reports for your property sets, including mobile usability report, apps, review your AMP implementation, double-check rich cards, or hreflang / internationalization markup, and more.
Google also said you can combine even more properties into one set, they said "you can now just add any verified properties to a set."
Here is a view of my property set for this site, with our app, multiple canonical versions of this site and more.
Forum discussion at Twitter.