That'll be a huge job even if you only ever look at one sector - take sport! Everyone who comes from industry could have a specific sport's NGB qualification/registration - often more than one per sport and that's just coaching! Then you'll have the exercise experts, and REPS possibly, or some providers have their own register - most supply registration CPD and insurance. THEN you'll have the outdoor ed stuff - lots there, at least one per activity. Then there's all the non NGB providers for coaching, leadership etc etc. As for number of subjects - who knows?? The number is likely to be enormous - chocolate making to aeronautics, physics to lace making! You can't afford to ignore the 'school' subjects as many FE lectruers in such subjects are, like me, FE certified, latecomers - I teach PE and psychology and could belong to 3 or 4 professional bodies for each!