There's actually quite a small number. At three moves, it's one of the stats with the lowest amount of moves that boost it.
- Acupressure, which increases a random stat; including accuracy.
- Hone Claws, as you mentioned. As well as accuracy, it also boosts Attack.
- Coil being the last one, which also increases Attack and Defence.
Excadrill can only learn one of the moves, which is Hone Claws.
Also, if this is intended to boost the accuracy of Excadrill's Guillotine, the formula works a bit differently. Accuracy boosts are not taken into account.
Accuracy = ((User's level - Target's level) + 30)%