Here are the attacks Claydol can learn by leveling up in Pokemon Sapphire:
Level 1: Confusion
Level 5: Mud-Slap
Level 9: Minimize
Level 13: Extrasensory
Level 17: Rapid Spin
Level 21: Psychic
Level 25: Ancient Power
Level 29: Imprison
Level 33: Future Sight
Level 37: Earth Power
Level 41: Reflect
Level 45: Light Screen
Level 49: Hidden Power
Level 53: Trick Room
Level 57: Psybeam
Level 61: Explosion
By breeding:
Egg Move: * Telekinesis
Learnset by level:
Claydol's learnset can be adjusted slightly depending on the level the Pokemon is at.
This list of attacks is comprehensive for Pokemon Sapphire. However, some attacks may not be available to learn until you reach a certain level.
Let me know if you need more information about Claydol or any other Pokemon in Sapphire!