Claydol

Claydol has a few very good movesets available to it, and is one of the few Pokemon blessed with optimal dual-STAB movesets. Without a doubt, it has the moveset to make for a large offensive threat, but its stats just don't allow it to shine like it wants to. That said, it's not all bad for poor Claydol; it's a decent defender with a variable moveset that can keep attackers guessing to a degree, though anything that resists both Psychic and Ground really doesn't see it as much of a threat.

Best PvE Offensive Moveset

• Confusion edges out Extrasensory, but they perform similarly.
• Psychic should be paired with the above for a full Psychic-type set.
• Mud Slap and Scorching Sands make for Claydol's most optimal Ground-type set.
• Earthquake is not far behind Earth Power in general, but it's still not quite worth considering.
• Gyro Ball has no offensive use.
• Shadow Ball is powerful, but lacks STAB.
• Ice Beam doesn't suit Claydol's role. 
• Rock Tomb is even worse. 

Best PvE Defensive Moveset

• Confusion and Mud Slap are the best general choices, though the former is neutrally stronger.
• Extrasensory is entirely outclassed on defense.
• Psychic and Ice Beam are preferred for their relatively early damage windows and 2 bars. 
• Shadow Ball is largely unresisted in general, but is relatively easy to dodge. 
• Earth Power and Gyro Ball are very slow for 2-bar moves, and the latter's coverage isn't particularly valuable either. 
• Scorching Sands is on a par with Earth Power, trading a bit of power for a harder dodge window.
• Rock Tomb performs similarly bad on defense.
• Earthquake is unviable for defense.

Mud Slap is Claydol's best Fast Attack, boasting high damage and decent energy generation. Ground is also a much better typing offensively than Psychic, further reinforcing Mud Slap's use over Confusion or Extrasensory.

Claydol has an absurd amount of Charged Attacks to choose from, but they are all rather costly so it is important to start with the cheapest options:

• Rock Tomb is Claydol's best Charged Attack - a 50-energy move with decent damage that provides coverage against Flying-type Pokemon. Its guaranteed Attack debuff synergizes well with Claydol's high bulk.
• Scorching Sands is another 50-energy move that further improves Claydol's Ground-type damage. It is also yet another debuffing option.
• All of Claydol's other Charged Attacks from this point on cost 55 energy or more. Ice Beam is an option to threaten Grass-type Pokemon
• Shadow Ball can be used to deal heavy damage to Psychic- and Ghost-type enemies that may cause Claydol significant problems
• Earth Power and Earthquake are redundant; Mud Slap and Scorching Sands offer more than enough Ground-type damage
• Psychic is a STAB option, but its poor DPE makes it not worth using.
• Gyro Ball is horrible.