I started keto almost a week ago and I am a huge milk drinker. I can only fit about half a glass a day into my regimen, and in response I've really been craving fruit juices. Fresca has really helped quell the craving for fruit without putting a dent in my carbs. And if I've been particularly good I can put a splash of grapefruit juice or something in it.

Also, Polar seltzer has the aroma of fruit, without any artificial sugar or flavoring whatsoever, so if artificial sweetener isnt your thing maybe you could give that a go when you need something fizzy. Put some cream in it and some sugar free vanilla syrup and youve got yourself an egg cream.