What are the best methods of identifying rewards that motivate your employees the most?

You cannot really have a product which can answer this problem.

Most importantly, what you need you can found in yourself, your main motor of self-motivation, your mission in this life, is YOUR VOCATION, because whatever happens, your passion, your VOCATION will be so strong that you will move your Will to overcome you. Look for a teacher of vocation, someone who with your knowledge can find in you, the vocation that you have. When you discover your vocation, nothing will be impossible for your mission in this life - NOTHING - and everything makes sense for your conscience, you can achieve to visualize things that no other professional can see, you generate knowledge of your own conscience, with high social impact for the welfare of all , You enjoy life doing what you just like, your vocation - your passion, you will do yourself, an unstoppable person !!.

I work in a consolatory dedicated to gamification and I am looking for the best way to explore what rewards will motivate better the employers of an enterprise

Hey, I flagged this as not a fit as it seems unclear what the question is asking. I was wondering if you could clarify a bit, what kind of rewards are you trying to explore?