https://electro-smith.com/products/daisy-seed?variant=45234245140772
cost about 31e Programming the Daisy is a breeze with support for a number of languages including C++, Arduino, and Max/MSP Gen~
https://electro-smith.com/products/pod
pod is basically above but everything wired
https://electro-smith.com/products/patch-submodule
this I am not sure of, maybe you need to wire everything
https://electro-smith.com/collections/daisy
https://www.sparkfun.com/products/10588
SparkFun Qwiic Keypad - 12 Button
https://www.sparkfun.com/products/15845
there is a place called partco in espoo
modular kits
https://www.exploding-shed.com/music-thing-modular-mikrophonie-v3/100267 50e
startup
https://www.exploding-shed.com/music-thing-modular-startup/100129
90e
https://www.exploding-shed.com/leafaudio-contact-microphone-6-3mm-1-4-connector/100314-15
contact mic 15e
https://www.exploding-shed.com/case/eurorack-power/
cases pod20 etc.