Effects that are instruments themselves

Recently been messing around with the Electro Faustus / Fuzzrocious Grey Fly pedal and have been enjoying the hell out of it. It got me curious as to which other effect pedals can act as tactile instruments themselves...

I'm aware of the theremin type pedals and Simon the magpie's diy stuff but outside of that don't know too many. Anything worth checking out you'd recommend? Thanks!