Anything modular synth related that is not format specific.
As of now, I have owned a Wiard 300 and studio electronics omega 8 and se-1x, being controlled and integrated with an Elektron rytm, analog keys, digitone and other gear. I have found it all routed together perfectly and plays so well. The Elektron gear works great for controlling the modular via cv and has so much flexibility in terms of cv configuration. In addition the digitone controls the SE gear via midi beautifully!! Love it all so much!!