Irn Bru is such a standard thing here that I thought you were joking - only in the US could any type of flavoured fizzy water be discussed so solomnly.
It is sold in original and diet forms in the local Tesco supermarket, along with ditto of dandelion and burdock, cloudy lemonade, and various fruit flavours.

Some drinks from my childhood which I have not seen for ages are the cream sodas, strawberry and raspberry flavours were the usual ones, though they were hardly distinguishable by tasting.

My current favourite bottled drink is summer punch, multi fruity with an aftertaste of mint and something else. It is rare to get a complex flavour in a pop bottle.

Some pops and squashes are more useful to me as dyes than drinks. When putting together various cloths for patchwork they can sometimes require an overall toning, easily done with a bottle or three of something cheap and nasty to give them all the same overcast.