Most yoghurts will have sugar as lactose is a sugar. It is not always added sugar. I find for me at least that it is the total carbs that matter. But we are all different.
The Natural Yogurts are best, Onken do a Natural Set Yogurt that is very creamy and delicious, also Lidl do a brand called Milbona, it's a Greek Style Yogurt and again it has a very creamy texture, probably better value than the Onken brand.