There are quite a few sources that Google wouldn’t show. Here are ways to search the deep web for what you want.
Here are some good suggestions for finding things that don’t show up in Google. It explains that the Deep Web and the Dark Web aren’t the same thing, provides a link to a list of Deep Web search engines, and other suggestions including using a different search engine than Google. Personally, I rarely use Google Search as I prefer to use search engines with more privacy. DuckDuckGo and Start Page are two good ones and can be set as your default search engines quite easily – usually through the Settings or Privacy areas in whatever browser you use.