May sound boring, but I find myself using dedicated attenuverters a lot with DFAM... And mixers are always in full use for mixing modulation sources and mixing the Subharmonicon's VCO outs for chords or pads. Consider a matrix mixer (like AI Synthesis AI008) as you can route FX sends with it. Farkas is right: an FX module might come in handy as well. Or you can use effects pedals via ADDAC Pedal Integrator or similar devices.
And a precision voltage adder might be very useful (like VPME T43 or Doepfer A-185-2).
Cheers and all the very best for 2022 erveryone :-D