Not really looking for a more "classic" sound. Rather, I'm looking for something that is theremin but not like what I'm getting from other effects. The Overtone pedal is what especially interests me. It seems quite different from other effects boxes I've played....Like a pitch shiftier, but not. But I'm not certain. Watched several demos of that pedal online with guitar--it doesn't seem to be a pitch shift pedal in the sense that I'm used to. But whatever it is, hearing how it affects the signal from a theremin is something I am very curious about.
I have a graphic eq already, but it's not something I want to gig with. The Boss pedal looks like a good bet. Also have reverb/delay effects...but they all have a lot of different modes (reverse, multi tap, etc.). Subsequently, I'm too frequently fooling with these multi-effect boxes. A combined reverb/delay with only a few knobs and no dramatically different modes will limit distractions (my propensity to not play theremin and spend a show fooling with knobs on my delay).
I played through a burrowed effects board that had some kind of harmonizer on it. Unsure what kind. It didn't respond to the theremin in a way that I expected it should if it had been fed a guitar signal. It was glitchy and wonderful without being so over-the-top or obnoxious.