https://www.gobilda.com/5000-series-12vdc-motor-with-8mm-rex-pinion-shaft/

The 8mm REX® output shaft will protrude 32mm from the face of the Motor Mount (SKU: 1704-1632-0001) packaged with the motor, so you have plenty of real estate to attach a gear, pulley or hub to, while still leaving room for an 8mm REX® bearing to add the necessary support.

This motor has a tested speed of 5800RPM.