What would you do with all of this information if you had it? A list of all natural and artificial flavoring compounds/molecules known to man would be massively huge. Studying the effects of even the most commonly used of these compounds/molecules would be a monumental task that would take an army of scientists several generations to tackle. Add in there that you'd also need to study these chemicals in combinations to understand interactions and reaction products. This would become not just a monumental task, but for all practical purposes, impossible.
Here's a cute little post I found about chemicals in apples.
That apple is full of chemicals! | I think it makes a good point, however the list of all the chemicals found naturally in apples would be much much longer. Do we need our apples to contain a list of components? I'm not asking this to be snarky. I'm trying to make the point that we are surrounded by chemicals. Nature is a giant chemistry lab and can produce an endless combination of molecules. It would be impossible to study and understand every single possibility.
Think about apple pie. A recipe for a simple home made apple pie contains about 5 'ingredients': crust, butter, sugar, water, and apples. If you were to break those ingredients down into their individual molecular components the list would cover pages and pages, even if everything you used was organic. Not many of us would stress about wanting to know every single molecule type present in our mom's home made apple pie, even if it was reasonably possible to do so. Even if we did have that information, what would we do with it? Would we know all the possible ramifications and effects of even one of the chemicals present?