From an older Scientific American article:

  Natural coconut flavorings, for example, depend on a 
  chemical called massoya lactone. Massoya lactone comes 
  from the bark of the Massoya tree, which grows in 
  Malaysia. ... This pure natural chemical is identical 
  to the version made in an organic chemists laboratory, 
  yet it is much more expensive than the synthetic 
  alternative.

I use them with powdered stevia, and sometimes erythritol or xylitol, to make sugar-free gelatin desserts. Also useful for such purposes are the bottles found near the baking supplies: vanilla, almond, and mint flavors.

Another cheap natural source of low-sugar flavorings can be found in the outer layer of citrus rinds. Lemon, lime, and orange zest adds a bit of [bitter] flavor that is still vaguely fruity.

You can also get powdered malic acid and citric acid in bulk, which will let you make things more tart without making them taste like vinegar.

While it is difficult to find some flavors/fragrances in the grocery store, some essential oils are marketed for cosmetic purposes, for DIY soapmakers or perfumers, but you have to be careful to buy them as food-grade and do your own research into potential toxicity if you ever intend to flavor foods with them.

Cocoa (with no sugar added) and orange peel is my favourite choice for the natural additives.

The artificial flavors are more or less the same. But it's very limited. There's no way to find the complex, more subtle mixes used in branded yogourths, say mango, papaya, kiwi, raisins and the more realistic fruit varieties.

I believe that the lack of choices is caused by the artificial bashing propaganda. People would not buy artificial flavors yet they're consuming them anyway, just because they're conveniently fooled by a few fruit bits in the mix.

https://www.amazon.com/dp/B00VMAZQL0

For every molecule like vanillin, which is a powerful enough component of vanilla that it can often stand in for the whole, there are dozens of molecules that produce variations in flavors when combined. Most humans can't tell the difference in a blind taste test in baked goods.

Furthermore, those support molecules can become easier or harder to taste in the presence of proteins, sugars, or non-aqueous solvents.

So if, for instance, you want to make your artificially flavored vanilla ice cream taste exactly like naturally flavored, the aromatic additive cocktail you must use in addition to the vanillin will need to have a different composition from another food-chemist's concoction for vanilla-flavored sugar cookies.

But even then, you will have to decide what kind of natural vanilla you will choose to mimic, because the country of origin of cured vanilla beans can be discerned by professional tasters and with 100% accuracy by chemical analysis!

It's only moot because it is possible for people to prefer the taste of the artificial flavoring over that of the natural flavor, not because they are indistinguishable from each other.

And as I mentioned elsewhere, compounds purified from genetically engineered microbes can still be called "natural". That seems to be a clear case of pitting the letter of the law against its spirit.

Edit: I mean natural in the vernacular sense, not in regard to whatever is allowed by food labeling laws. That sense is "natural", in scare quotes. Natural coconut flavoring can only come from actual coconuts. "Natural" flavoring can come from the bark of an unrelated tree, beaver butts, engineered microbes, mushrooms, or anything else that could grow in the wild if it were released there. Artificial flavoring comes from a biochemist with a tank of ethylene and a CRC manual.

See another poster's comment here about natural coconut flavoring, which comes from the bark of a tree and not coconuts. In many, many cases, "natural" flavoring is literally the exact same compound as "artificial" flavoring, just extracted from a source in nature.

Honey can also be "laundered" by feeding it to another hive, then extracting from their combs.

There is no scanner app. If it's in stores, its origin is suspect. Buy honey directly from your local apiary. They will be able to tell you exactly where the hives were feeding before the honey was harvested, and the honey from some locations, or from single-flower honey, has a very different taste than the store-shelf-standard clover honey.