Motors and Legality

We are currently looking at different motors and were wondering whether or not stepper motors were legal. If so a link to legal ones would be great. Thanks

Please read the rules manual for this answer. Specifically R33.
If the motor is not listed, it is not legal.

Also, the list of permitted motor controllers (R35 a). All brushed, apart from the Nidec integrated brushless controller/motor. No stepper motor controllers.

You may be able to achieve similar function using a legal DC gearmotor with encoder feedback. It will take a bit of coding, though. For small positioning tasks perhaps a servo will do?