Apple pencil

There is no way to find a lost Apple Pencil except by actually looking for it.

If its close enough to the paired iPad, it should appear connected in Settings->Bluetooth or in the Battery Widget. You can then search with 30 feet of the iPad for it.

To replace the lost Pencil, you would need to buy a new one. Link-> Buy Apple Pencil - Apple

There are no technical means by which a mislaid Apple Pencil can be located. Even if still charged, a motionless Pencil will shut-off its Bluetooth connection to save power - after which if cannot be detected.

The only method to locate a lost Pencil is the Mark1 eyeball...