Lego Breadboard mount: https://www.thingiverse.com/thing:3622179
Custom gears: https://www.thingiverse.com/thing:4258996
Lego N20 motor mount https://www.thingiverse.com/thing:3968044
Custom part designer: https://marian42.de/partdesigner https://github.com/marian42/partdesigner