In the US there are basically 3 (maybe 2) Young Again Zero Carb (Only available online) Wysong Epigen 90 and Evo (Evo has a new formula that may not make it have more carbs than it was before).
I tried Epigen, (not Epigen 90) for 8-10 days, Epigen is starch free and low carb, blood sugar definitely decreased to blue numbers, but 2 of 3 of my indoor cats (maybe all of them) developed diarrhea. Took them off it two days ago, so be careful.
young again 0 carb is a good option for 0 (net) carbs dry food-- just beware that the sales force is very aggressive and make claims I personally feel are not responsible and maybe even dangerous for a newly DX kitty-
My non diabetic eats it because we are on tight reg and my FD kitty can only have wet food but he has tried it and he was not going crazy for it but he is not very food motivated--the other one eats it minimally-
I don't have any other dry in the house ... could have something to do with it? I do think it is the best of the dry as far as carbs-
Nature's Variety Instinct is low carb. One of my diabetics goes off his wet food fairly often (he's 18 and has a bunch of other issues). He does love the Instinct Chicken and has some every day, sometimes as a topping on wet food or just by itself. My other two diabetics get a small amount for treats and it's never had any obvious impact on their blood sugar.
I feed YAZC however the one thing is if you free feed it as well as feed wet food your cat will more than likely gain weight and that's not good . If you do feed both I would really limit how much of it you give your cat.