@LostInParadise They can retrieve almost anything. And their programs automatically scan all your email and messages on gmail and Facebook and other such sites and apps.
You can see what they show you about what they store on you at Facebook on their web site. Click the upside-down-triangle-in-a-circle in the upper-right-hand corner. Then click “Settings & Privacy”, then “Privacy Shortcuts”, then “Your Facebook Information”, then “Access Your Information” to see 27 colorful categories of information on you. And/or click on “download your information” to get a copy of it as a file.
Of course, that’s not all, as Facebook owns and trades with several other companies that also collect info on you.
Meanwhile Google tracks and analyzes all your ingoing, outgoing, and draft mail in gmail, your web and app use, your location, and data from it’s companies (e.g. YouTube). Google has also admitted that they have done experiments to see how they can influence voters via very subtle changes to what search results come up for them, and in what order, which could be automatically done for entire populations based on analysis of all the data they have on everyone. They calculate that the amounts they can shift votes tends to vary more than votes themselves tend to vary, so if they chose to, they could probably determine the outcome of just about any vote. Also, people who have spoken out about Google have sometimes found that they can no longer access their gmail, or google, or the Internet itself.
If you carry a cell phone in your name, your cell phone company, smart phone manufacturer, and government security agencies, can access where your phone was and is, for years of history.