The other main options are tartaric (grape) and malic (apple), or you can buy a blend. Raspberries are naturally high in citric, but sour beers are typically lactic. Personally, I don't think it makes much difference which one you use; your tongue will process all of them as sour. Dissolved CO2 is also acidic, and serving it cold will mute the other, more subtle flavors, so make the beer a little less acidic than what tastes best flat and warm.
Say no to intolerance: love gluten and lactose.