I was recently at the store trying to find something I could drink that did not have carbs, sugar, artificial flavors or sweeteners. One of the items that I found in several flavors was Polar Seltzer.
The store was having a buy 3 sale so I picked Black Cherry, Orange Vanilla, and Ruby Red Grapefruit.
With my first taste, I found the seltzer overpowering, however I later discovered that if I just pop the top and stick it back in the refrigerator for a bit or overnight it's pretty much just a lightly flavored water.
So yes, if you're looking for a zero carbs option, I recommend trying Polar Seltzer, and checking the labels of other seltzers.