Do you already have this selection of modules? Or are you planning to get them?

The biggest immediate need I see is for some modulation sources, and VCAs. I'd suggest something like Pamela's New Workout (8 linked clocks, LFOs, etc.) or Quadrax (4 modulation sources which can be anything from envelopes to LFOs, with lots of CV possibilities, along with something like an Intellijel dual VCA, or Veils, Tangle Quartet, or any other multi-VCA module. There are a million options out there, but these are crucial parts of any modular system.