I'm not sure what you're looking for if you have a rough understanding of how Google's ad business works. They track as much as possible across every website and app that loads their analytics, which is most websites and apps. They don't sell user data or allow access to it (unlike Facebook, like with the Cambridge Analytics scandal). However, they don't have to sell the exact user data when everything is hyper targeted in ad exchanges. What's the difference between selling user data (location, age, gender, browsing history, etc) when they can instead sell an ad to someone who requests (city, age range, gender, keywords).
Everything Google does is centered around maximizing the amount of data they can track and use to sell targeted ads. If a Google service isn't scraped for behavioral data (e.g., Gmail), that's only because of backlash. Removing third-party cookies in Chrome is years later than originally promised and only comes long after Safari and Firefox have blocked third-party cookies in the default configuration; and it only comes with a client-side snitch for ad targeting data.
That's ignoring all the ad fraud, malware delivery, and other shady stuff of the actual ads business, separate from the privacy issues of behavioral data intake and processing.