Sell it to people who will manipulate you and your family. Even subtle changes could shape the direction of your life. Or, they could say people with your preferences are in a certain area and fund some other area instead. Could be anything. The less data they have, the better.

Edit: gave->have

Have health insurance?

Big into drinking, lots of bars and going to liquor stores whilst your mobile phone is with you and some apps have location access permissions?

Don't be surprised if your health insurance goes up on account of being in a higher risk group...

(It's not exactly hard to cross your location with store locations and it's probably already done generally to try and determine your consumer habits)

And this is just a mild, mild example. Stuff to do with people's sex life can have far more entertaining effects, especially in a highly moralistic country (like the US) or if cheating on a spouse.

Think about it this way: if you don't jump through hops to make it hard to track your location, there is a record, forever of every place you go to with your phone and how long you stay there (and repeat visits with long stays would signal a pattern) as well as of everything you're interested in enough to look it up and/or visit it on the Internet and it's all crossed. Further, if you have email via one of the big providers such as Google, every email you sent, received or even just drafted but never sent is tracked.

Why do you think Google started pretty much forcing people to give them their phone number for the Google account that, for example, goes with their Google Mail?! It allows them to link all that sweet information and match it to a single individual.

And this is before we go into crossing data with the kind of physical life data on you: the insurance company records, car onership and rental, financial information and transactions, even public transport use (for those which use modern touch-in touch-out cards).

sell it to police. sell it to a stalker or vengeful ex. sell it to prospective employers, landlords, debt collectors, and scammers. this is just a taste, off the top of my head.

Right now in the US? Not much outside of try to sell you stupid shit.

But the capability in the data is there for an authoritarian regime to do quite a lot to you as a result of the information.

So you know - if there was any pending threat of a narcissistic psychopath upending the government you might be concerned over what insights into individual mindsets can be accomplished with the data available...