If you don't have time for Google hacking, you can try to use www.archive.org. Once upon a time, people didn't care as much as today about their privacy and security settings and they used to share much more than they should on their websites. When I used to do penetration testing, Archive.org was my first stop to check whether I could collect information that might be much harder to find.
As an example, you can see that my blog was saved 73 times between April 26 and September 2017; trust me, even I don't have all those backups stored anymore:
A snapshot of my blog from 2011:
