I guess simply 'milk' I also missed, which is a bit sweet of course but I wasn't intending to lump it in with fruit juices and added-sugar drinks.

I did almost mention jaljeera, but thought that might be a bit niche. It is also often sweetened though. I've never known not-sweet lassi though? Salted lassi is still sweet underneath, like salted caramel, ime. We could count it with the sweet-ish milk drinks, anyway.

Lassi is a traditional drink where I’m from and contains only salt traditionally. Sweetened lassi is a relatively recent restaurant-led innovation. When I was a kid “lassi” meant salted; you had to specify “sweet lassi” for the sweetened version.