While sacrificing accuracy compared to a crystal, a few automotive clocks used a pendulum oscillator, this was a ring with a magnet attached at 1 point, it had 2 drive coils and 1 sense coil, and a restoring spring.
When the magnet went past the sense coil in 1 direction it gave a positive pulse, in the other a negative pulse, which drove the transistors operating the drive coils which gave it a small kick to keep it moving.
I have only repaired 5-6 of these in the past, however almost all of them operated at 2 Hz,