Club soda with anything, syrups, bitters, citrus, is the secret for a happier sober life. not to mention is usually free in bars. (bitters are technically alcoholic, so that is a personal choice)
soda + bitters is super tasty. if you're in a fancy cocktail bar (which I'm not that often these days, because drunk people are annoying when you're sober), most good bartenders will be happy to concoct "something tasty" and non-alcoholic, too.
Ginger beer (as in fancy ginger ale) + lime juice + bitters, well-iced, is quite tasty. It's a Moscow mule without the vodka. You can mess with adding tonic water if you miss the vodka taste. A splash of Luxardo syrup, cherry juice, blueberry purée, of any number of other little flourishes (lychee is notably great, tumeric is interesting) can make it extra special. I drink occasionally but I also enjoy these NA concoctions. It helps that I don't have friends who make it weird for anyone to not drink alcohol when we're out or at parties.