I'll strictly speak about Google. (and assume that you are a regular internet user, who has gmail, and doens't go to great lengths to mask their activities)
If they wanted to be really invasive, they could get a lot. Not saying that they are doing it, but they can
1) Birthday - on every birthday, there are a bunch of random sites where you have an account that send you congratulations.
2) How old - beyond patterning (which can get you within a fairly narrow range), I am sure that most people have received or sent an email which states their date of birth - whether in the text, or as part of a form
3) Job changes - in any european country, you get your employment contract via both mail and email. (and btw...this means they have your salary too)
4) College you went to - if you already had gmail while at university, they have you. if you got it afterwards, they probably saw the "alumnus" emails
5) Relationship status - this is arguably trickier. There's no "hard" proof. I think FB has the edge here, though not as large as it used to be (I remember that 10 years ago everyone had their status on FB. now it's almost no one, but it's irrelevant, because they can look at your photos, and whether you mention "gf/bf/wife" etc.
6) Running - again, FB have the edge in determining how much/where etc. But google know you are running, because they have your emails from the apps to which you subscribed.