For me it’s the Verbos Scan & Pan. It’s the module I’ve owned the longest, and the one that is always used—of course, it’s my main mixer, so that might be part of it! But beyond that, it’s helped me dedicate my standalone VCAs to modulation use since each channel has one built in, it has great gain saturation for coloring which helps me get more out of simple waveforms, and the scan/pan/width controls let me use the mixer in so many different ways. I can use it as simple stereo, but also sending to different effects and wiping between them, or as wet/dry instead of L/R, or as a kind of rough cadavre exquis. It constantly inspires me to patch differently.