I build open-source Eurorack modules, I can sell you some.
Nearness, Forks, Clock divider, MIDI 4+1 and In CV are among joeSeggiolas most popular products.
Italy
joeSeggiola
3x4-way multiple and 2xAC coupling module
Programmable Eurorack clock divider in 4 HP
Through-hole Arduino-powered clone of Mutable Instruments Branches
Terry Riley's "In C" implementation for Eurorack
MIDI to 4x CV/gate, with polyphonic and monophonic voice allocation modes
Minimal panning mixer
How much is the fish?