I am a foreigner who has lived in Suzhou for many years. According to my experience, Suzhou cake balls are mostly filled with glutinous rice flour, with bean paste, sesame sugar and other fillings, such as Chongyang cake, Ding Sheng cake and Dafang cake. I can't name many names. They taste soft and tough, sticky and chewy, and I like several of them. However, according to my observation, many old Suzhou people like to eat the kind with suet, which is slightly salty. Few foreigners like it, and I am not used to it. There is also a kind of meat dumpling, which is white glutinous rice dumpling. The boss will pour soup into it before the guests take it away. I don't like this either. Most of these authentic Suzhou pastry shops are located in traditional food markets and patronized by old customers. If it's just for a few days, try buying some in the tourist area. If you are here to taste delicious food, I recommend two places: Fengmen Hengjie and Shili Shantang, and you should eat generous cakes when you go to Luxiang (this is a bit far).
Huang Tianyuan, if you are not in Suzhou, you can buy it on Taobao.