Thread: MI Rings, similar modules?
All the popular physical modelling units have been mentioned. I don't think there is much else, other than the 2HP units like Pluck. To go further into physical emulations in one module would require prohibitive amounts of DSP.
It might be more fun to study how the physics works and build up your own set of modules to experiment. If you don't have a copy of The Computer Music Tutorial by Curtis Roads, this would be a good excuse to invest.