Not 100%, but I'm guessing stevia sweetener drops.
It's something she just does for flavor, not an integral part of her diet.
If you experiment, I'd look for something with pure ingredients, never with added alcohol.
Don't use em myself, so you'd have to ask her, or keep looking through her vids.
I think they're essential oils.
Unlikely Free would be recommending anything containing oil, as it's against our guidelines.
Actually, to paraphrase essentialoilcookbook.com:
"Unlike fatty oils such as olive oil, flax oil, sesame oil, avocado oil, soybean oil etc. essential oils contain no glycerol molecules that give a characteristic slippery texture and leave a greasy residue. Fatty oils and essential oils are different. Distilled essential oils contain no fat whereas fatty oils are 100% fat."
Regardless of weather she recommends anything containing oil, I believe that is an invalid reason. Freelee also promotes the consumption of onion and products containing garlic/chilli on Youtube, which are also against 30Bad guidelines.
Funny to hear that since she's a founder of 30bad. :D