Search operators are a fast way to check what Google holds, provided you understand their limits.
Useful operators
site:example.com, pages indexed for a domain.site:example.com/blog/, narrow to a section.site:example.com "exact phrase", find duplicated text across your own site.-site:example.com, exclude your own domain when checking for scraped copies.filetype:pdf site:example.com, find indexed documents.cache:, retired; use URL Inspection instead.
Important caveat
The result count for site: is an estimate and often wildly inaccurate. Use it to spot the presence or absence of pages, never as an index-size metric. Search Console gives the real number.
Alien Road recommends: use site: with an exact phrase to find internal duplication before you buy a tool for it. Searching a boilerplate sentence across your own domain surfaces template duplication in seconds, and it is often the fastest first look at a thin-content problem.