I sold a Grand Moff distortion effect pedal I designed on Etsy. I don't know if I'll be building any more distortions because I'd like to focus on synth modules and effects pedals.
I've been messing around with what could be a modulated filter pedal, using an MS-20 style low pass filter modulated by a triangle/square wave LFO, powered by +/-9VDC from a MAX1044 integrated circuit. I've even got a PCB in the works for this.
I built a 19" 6U rack space out of an IKEA RAST bedside table. I stained the pine wood black and drilled some holes to mount the racks with some heavy duty screws. It turned out beautifully, really happy with this build. I've left the wood unfinished but it's something I could possibly revisit if I run out of other projects to complete (hah!).
I've been building a modular analog synthesizer. I've populated one frac rack with a PAiA 9700 series MIDI-to-CV converter and a dual VCO (plus AR envelope generator), a Music From Outer Space dual linear/logarithmic VCA, an adjustable regulated AC to +/-DC power supply (I'm running on +/-15VDC), a MFOS state variable 12dB filter, and one DIY module that's a little more... esoteric. In the past couple years I've accumulated a few glorified potentiometers: two Radio Shack TRS-80 joysticks, and one Ensoniq CV foot pedal. The TRS-80 joysticks use male 5-pin DIN plugs very similar to MIDI plugs, except the pin spacing is slightly different, and the Ensoniq foot pedal uses a stereo 1/4" jack. So, my DIY module is a way for these controllers to interact with the modular, to extract CV signals from them. It's basically a bunch of jacks (DIN-5, 1/8", 1/4") mounted on a panel and connected to the power supply.
I also purchased an Arduino and have been experimenting with that. I fear I'm spreading myself thin with too many projects!