I have to imagine the Federated Suns makes use of a lot of simple towed Artillery pieces. They don't have a huge selection of delivery vehicles. That said, as have already been mentioned, there are a number of generic platforms going around, including the Mobile Long Tom, Marksman (production restored in the 3060s in Lyran space), Arrow IV Demolisher, etc. As far as Federated Suns specific platforms, I can only think of a few - the aforementioned Yellow Jacket & Pilum, the Legionnairr variant, and the new LGB-8V Longbow from ONN should be available, as it's converted from Crofton built LGB-7Vs. Since the Federated Suns doesn't have a lot of unit's with TAG, however, I tend to stick to towed Long Toms and Aerospace Fighter delivered Arrow IVs when I play them. Long Tom is far superior to Arrow IV when homing missiles aren't an option.