Okay, well, Faeries finest flavor extracts have, at minimum, PG, or Alcohol. I am a little iffy on the fact that they don't offer an ingredient list for their extracts. They have all natural flavorings, but that's not really saying much about what else is in it.
Bakto flavors does have ingredient lists for each flavor, so that's better.
For either of these companies I would:
1.) Avoid any that contain oil(s), though, some use oils with no issue.
2.) Email/contact the company, and ask for ingredient lists for flavors you are interested in.
It's always better to know what you're buying. If I were to try one or the other, I'd try the Bakto, simply because they're more apparent than the other site.