I find making suggestions for this one a bit difficult. All your voices are pretty much standalone, with the envelopes and filters on the modules themselves. So you don't really need anything in that aspect.
I think that if I were to add anything to make this rack more complete, some extra envelopes/LFO or utilities would be the first thing on my mind.
I agree with the Intellijel quad VCA you mention.
Intellijel Triplatt - three channel mixer and attenuator. You can use it to combine your drum section and feed it into filter or effects. It will also help you shape your modulation by attenuating LFOs or envelopes. Without something like this, it is difficult to keep the LFOs from modulating things too hard. The Quad VCA can do something similar. Or Happy Nerding 3x MIA. Or even something super simple like Doepfer A-183-5.
Xaoc Devices Zadar or Batumi - The first one has a screen and four envelopes or LFOs that you pick from a list. Best enjoyed on a bit slower music. The second one has four traditional style LFO. Either one of these will create movement in your sounds.
Alternatively Make Noise Maths, Befaco Rampage all give two snappy envelopes with extra complexities.
A mult.
These will help you achieve the most with the modules you have already bought. Other than that, I suggest you to hook it up and play with it and see what you would want more of.