What's a good barbecue sauce recipe without sugar?

All my BBQ sauces start out with either tomato passata or tomato ketchup. These are sweet enough without added sugar as long as you tone down the sourness by using a little less vinegar.

Fruit juices and sodas are also a good idea - orange BBQ and Cola BBQ are just two I've heard of. Do a quick search - I couldn't give you a link to one because there's SO many! (If they require sugar, just tone down the vinegar to compensate).

You can also avoid grain sugar by using something natural like honey (good when paired with mustard, of course) - this provides natural, flavourful honey sweetness without the sickly-ness of refined sugar. Especially good if you use an artisan honey such as Lavender honey - experiment as they all have different flavours.

You can use honey in place of brown or white sugar in any BBQ sauce recipe.

You can use a fruit juice that would work with whatever you are cooking. Orange or apple juice, a mango nectar, pineapple juice any of these would work well for chicken, pork, fish, or beef.

If you cook it down long enough adding whole fruit would also work. Apples, oranges, carrots are very sweet as well and grated would breakdown and add sweetness. I would strain the sauce to eliminate the strings of carrot though. I think bits of apple, pineapple, mango would be more acceptable than strings of carrot.

Just eliminate the sugar in any recipe. It is NOT really necessary.