the complimentary timetable issued by the operator of FRA lists both passenger and cargo flights. All FX flights to and from FRA are listed in there.
It´s of course not the complete FX system schedule you´re looking for, but it´s at least a start. I´m sure Fraport would send you such a timetable if you contact them via eMail or their website.
Hope this helps at least a little.