Indian tonic water is quite nice and grown up I find . I loved trying all the olde worlde traditional ginger beers /lemonades. Iced Tea/Clearspring green teas /Fruit teas like Rhubarbs and Blackcurrant Coconut water San Pellegrino water plus their fizzies are lovely Dandelion and Burdock Belvior do some nice cordial mixtures like cinnamon , plums , rhubarbs etc. Juices like pomegranate I think you should just make it your mission to try lots of different soft drinks . Good luck !