I'm rebuilding the electronics of my Rapman 3.1 as well and identified the stepper motors as these:
M57STH51-3008DC (Nema 23, X Y Z)
https://www.motioncontrolproducts.co.uk/products/2/5/nema-23-57mm-high-torque-stepper-motors/
https://www.motioncontrolproducts.co.uk/productimages/cms/M57STH51-3008DC-S(rev.C).pdf
M42STH47-1684SG (Nema 17, extruder):
https://www.motioncontrolproducts.co.uk/products/2/4/nema_17_high_torque_stepper_motors/
https://www.motioncontrolproducts.co.uk/productimages/cms/PDF/FL42STH47-1684A-01(RevA).pdf
M57STH51-3008DC (Nema 23, X Y Z)
https://www.motioncontrolproducts.co.uk/products/2/5/nema-23-57mm-high-torque-stepper-motors/
https://www.motioncontrolproducts.co.uk/productimages/cms/M57STH51-3008DC-S(rev.C).pdf
M42STH47-1684SG (Nema 17, extruder):
https://www.motioncontrolproducts.co.uk/products/2/4/nema_17_high_torque_stepper_motors/
https://www.motioncontrolproducts.co.uk/productimages/cms/PDF/FL42STH47-1684A-01(RevA).pdf