We’re working on an option in highlighted content to enable custom queries where you can provide the KQL or CAML and specify your own query. This will enable you to search by custom content types.
56 votesthinking about it · AdminSharePoint UserVoice Admin (SharePoint UserVoice Admin, Microsoft SharePoint) responded
Thanks for your feedback! We’re reviewing your suggestion. Remember, the more votes a suggestion gets, the more likely it is that we’ll do it. You can see what’s happening with Office 365 on the Office 365 Roadmap.Anonymous commented
This is greatly needed!