Probably a boring answer but I know my grandmother’s credit card information. I live with and help take care of her, so she doesn’t mind sharing it with me. Not like I’m planning to do anything nefarious, but I guess technically it could ruin her financially.
I’m a financial services professional with access to so much info that could be used for identity theft and other nefarious purposes. I’ve been doing this forever and still feel weird asking people for their checking account info.