I recently picked up an MI Audio Pollyanna, which is a fantastic MXR Blue Box-esque pedal on its own, but it also works well as a complement to the WMD Geiger Counter, particularly on the more complex wavetable settings. The Geiger Counter will take any signal that either has a low fundamental frequency or is deficient in upper harmonic content and will add a ton of harmonic overtones to that signal — add in a volume pedal (or any type of ADSR pedal like the old Boss Slow Gear) in front of the Geiger Counter, and you’ve got some pretty dynamic digital synthy tones to work with. The resulting tones sound a lot like a cheap old FM synthesis keyboard to my ears.