Your GPS location (if you have it turned on), your SMS messages, your call logs, your phone's storage, your camera, your mic... Just read the permissions: https://play.google.com/store/apps/details?id=com.facebook.o...

I've never had a Facebook app on any of my phones and I will never install one.

Worth pointing out: Luckily, my phone came without Facebook apps preinstalled, so I had the choice of seeing what Facebook wants to access. Other people don't even have that chance since it comes preinstalled in most of the cases.

But they have that data through their regular Facebook app (I wonder if that's next).

Also I'm on iOS so I can deny access to Gps/location/camera/mic and there's no way to access my message history.

Thanks for the reply though!

That's exactly why many don't run the official Facebook either. There are third party apps using the web-interface meant to sandbox Facebook so they can't gather all information. Up until now those web-interfaces have also been able to use the chat though. And you can still do that with some quick apps made to work around this block by facebook.