Google has just added a new Personal tab for results to search. Now if you toss in a term that might not otherwise trigger the personalized search results feature, you can manually move over to the Personal tab and make sure that compatible results appear. Results there can be easily limited to the content of your Google account across the company's various services. Searching for calendar appointments or emails just got a little bit easier.
If you don't see the tab on a given search, it should appear under the More button. To smooth over any paranoia it provides the same message that personalized results did previously, only you are able to see the results displayed in the Personal tab.
The change is live on desktop and mobile, though on your phone it is a bit harder to find. You have to scroll over quite a bit to get to it. I was able to pull up a good variety of personalized results from both, including emails, calendar appointments, and images in Google Photos. Searching for content from other Google services like Keep or Drive, unfortunately, didn't work. But, perhaps support will be expanded in the future.