I love Fresca, but yeah. Between metformin and chemo drugs no grapefruit soda at all. I am very sad about this.
Zero Sugar A&W Cream Soda and Zero Dr. Pepper with Cream Soda.
Both really good, but hard to find.
I’m still a big fan of good old Coke Zero too.
I recently bought a case of “Coke No Sugar No Caffeine”. It’s decent. I joke with my friends “it’s the least Coke of the Cokes”. 
My favorites:
Diet Coke
Diet Coke Vanilla
Zero Sugar A&W Root Beer
Zero Sugar Squirt
Dr. Pepper with Cream Soda & Fresca also, but I don’t remember if they’re “diet” or “zero sugar”.
Diet RC is great but very difficult to find.
Yes, I love Sparkling Ice. It’s a sweet fizzy drink, which is enough for me to call it “pop”, and no calories or caffeine. They have a nice variety of flavors and not too expensive when buying a case at Costco.
They Do make 50/50! I swear its the same as Squirt.
I like Bundaberg Diet Ginger Beer, it has a nice hint of orange flavor along with the ginger bite.
50/50 is now made by Dr Pepper Snapple Group, which, BTW, also makes Squirt (they used to be a client of mine).
For something that is both fruity and fizzy, there are plenty of sodas that are 50% juice and 50% water, or you can trivially mix them, but real fruit juice obviously has a lot more than “no” sugar, unfortunately.
Drinks like Fever Tree Ginger Beer would also be good but they add sugar—the low-sugar one is roughly like 50% grapefruit juice.
pkbites, you are kidding, they make a zero sugar Code Red??? I used to love Code Red, then it was gone. It’s back? Shit, I have to go to 3 or 4 stores just to find a week’s supply of zero sugar Mt. Dew, digging thru the shelves for the black top on the bottle.
You can get it on Amazon for an exorbitant price . Sadly it is limited and regional in distribution. If you’re not living in parts of the Midwest (so I understand), you’re shit out of luck.
I like Zevia sodas. Sweetened with stevia extract which seems rather polarizing.
Yeah, stevia just doesn’t work for me. To my taste buds Zevia tastes vile. But no accounting for taste - I know someone who swears by diet Dr. Brown black cherry soda and again there is something about it I just don’t like.
I think most diet sodas are probably kinda polarizing. For me old Coke Zero = fairly good, new Coke Zero = barely adequate, Diet Coke = awful. But I’m sure you can find people that would reverse that order.
I love Canfield’s Diet Chocolate Fudge Soda.
My Beloved says that I am living proof that it is possible to survive without the benefit of taste buds.
I love Coke Zero. But right now thanks to chemo it tastes …off. Like, not really there. Cherry Coke Zero is great, though.
I don’t know. Allegedly they do. I never see it in the Milwaukee area. Like never ever.
Canada Dry Zero Sugar Ginger Ale.
I also like some of the Fanta Zero flavors in the fancy Coke self-serve soda fountains. Particularly peach. Wish some of them were available in cans.
Diet Pepsi has always been my go-to soda since I was a kid but I’ll get Coke Zero Sugar around the holidays (it’s kind of part of the holiday menu at our house). 7-Up Zero Sugar is also good. Diet Shasta, which is a generic soda found at WalMart and a few other chain stores, is actually better than Diet Pepsi to my taste buds.
I rarely drink soda anymore – I stick to water or tea most days – so am probably not the best judge.
Okay, enough nuclear war crap. I’m going to return to something vastly more important - my highly subjective analysis of most of the currently available Diet/Zero Sugar Mountain Dew flavors (I think I may have tried them all at least once out of curiosity):
Diet Mountain Dew - the OG. Surprisingly similar to standard Mt. Dew. I think the sickeningly sweet flavor (which I rather like) is more easily imitated for Mt. Dew than for most diet clones. If you like the sugar version AND can tolerate diet soda, it’s a very reasonable substitute. Still being produced in parallel with…
Mt. Dew Zero Sugar - very similar, NOT quite identical. This version ups the caffeine by ~20% and has a subtly “crisper”/“cleaner” flavor. I prefer the flavor of the original diet by a hair, but they’re close enough for government work.
Mt. Dew Code Red Zero Sugar - “cherry” flavor. Hard to find (or just expensive to order), but I’m fond of it. Probably my favorite.
Mt. Dew Major Melon Zero Sugar - “watermelon” flavor. Easy to find, decent IMHO - it’s grown on me.
Mt. Dew Spark Zero Sugar - “raspberry lemon” flavor. As above. Widely distributed, pretty decent. On a par with the Major Melon line.
Mt. Dew Baja Blast Zero Sugar - “lime” flavor. Ported over from a Taco Bell exclusive to retail. Very intermittently available. The only time I tried it it was near expiration, so I couldn’t say if that hurt the flavor profile (probably), but I wasn’t impressed. I had expected to like it - I usually like lime-flavored most anything. But it was more distinctly “dietish” than some of its cousins. Again might have been the expiration date issue.
Mt Dew Frostbite Zero Sugar - “melon” flavor. Walmart exclusive, intermittently available. Tried it once, unimpressed.
Mt Dew Voodoo (version 4) Zero Sugar - “mystery” flavor, but these are Halloween seasonal exclusives and seemingly always candy flavored - this one tastes like SweeTarts to me (other people say sour patch kids). Fall limited edition. Never tasted the previous three. Tried this one and flavor was as above. It was…okay. If you liked Sweetarts as a kid, which I kinda did. But I’d never buy it again.