I recently purchased a Behringer 914 (Moog modular in Eurorack format) Fixed Filter Bank module, for a price so low that I couldn't build it for the price. I subsequently bought the Behringer 960  Sequential Controller, a 921 VCO, a 904A low pass filter, and I'm waiting for a 902 VCA to be delivered.

I just completed assembly of the (excellent!) AMSynths AM984 Four Channel Mixer PCB, this is now waiting for a panel.

Note that, as designed, the Mixer draws approx. 60mA per power rail (Rob of AMSynths has confirmed this) and hence the 79L06 regulator runs "warm" - use of a TO92 clip-on heatsink is recommended.

I'm planning on developing the following DIY modules to match the Behringer "Moog" series:

995 Attenutators (panel only) - the Behringer module is overpriced IMO.

994 Mults - ditto

993 Filters, I have a small stock of vintage "tropical fish" capacitors. This will be DIY (PCB, panel) only, as AMSynths already sells an assembled version of this module.
992 control voltages - as the Behringer module, but without the front panel jacks for "behind the scenes" CV buses.
901B Oscillator and 901A Oscillator Driver. This is the original Moog modular VCO, which has a number of "quirks". It needs rare parts  - I already have my personal stock of CA3019's waiting.

Prototype for a 10HP CV to MIDI (not MIDI to CV !) converter. Driven by an Arduino NANO, the software will be open source in the true sprit of "DIY" - if you don't like it, change it.

Five front panel CV inputs, plus an optional one on the PCB. All of the panel controls (including "attenuverters") are software controlled, so can be re-assigned to other functions if required.

The 26-pin connector is for a "Waveblaster" compatible MIDI sound generator card (available commercially, a DIY version is under development).

The module is also designed as a general purpose Arduino based development platform, so has optional sound input, PWM sound output (MOZZI compatible), MIDI input.