Nuclear subs are electric, so no gears. Idea still could probably work for some applications.

Google for "weston bye magnetic gear clock". Note its not as convenient as you might think... no ferrous material in the construction or it'll build up on the magnets until it hits something, and no pendulum designs, or none with conductive material due to magnetic braking.

It turns out the inherent mechanical limitations override the low friction advantages pretty much everywhere.

For practical engineering work most frictionless applications either need to handle 100+ HP to make economic sense, which isn't happening, or what they really need is sensing with no stick/slip friction and we have rather advanced and cheap optical position sensors and other non-contact sensors now a days.