I revisit this same exact "problem" every so often myself.... lol... I too have never really found any "sweetners" artificial or "all natural" ones (whatever that means most of the time...lol...) that I cared for... I was using nectresse, which I thought tasted ok, but I never really loved it... I used to use Sugar in the Raw and since I don't like my coffee overly sweet 1tsp was all I needed and I even could get by with a 1/2 tsp sometimes... and like you say the carb and calorie count is pretty negligible if you are only using a tsp... At that level for me I don't seem to have any unusual cravings and I lost weight just fine...
Also I'm not sure if you put milk or cream in your coffee... But when I was doing very low carb I found that just using 1tsp of cream in my coffee (no sweetners) gave it a richness that made it taste sort of "sweet" to me, so that would be about 17 calories all which would be from fat... And I've also used all sorts of soy, almond, and coconut "milk" creamers, most of which have some sort of sugar in them, but the carb counts usually weren't that bad.
Ultimately though it turns out I've lost 50lbs having about 3 cups of coffee a day each with about 20 calories in it... Some days all those calories where from fat and some days all those calories were from carbs... So I might have been making myself a little crazy for nothing... But hey, that's nothing new for me... Lol...