What generation is this? That can make a huge difference
Surf
Psychic
Trick Room/Thunder Wave/Calm Mind
Shadow Ball/Ice Beam
BTW this is for Slowking
There are so many moves I would want for a Slowking. Sigh...where to start. Psychic and Surf are there for STAB. Trick Room can bypass Slowking's abysmal speed by letting it attack first for a while. Thunder Wave additionally may allow Slowking to strike first. Calm Mind will increase Slowking's already high Sp. Attack and Sp. Defense making it that much harder to beat. Shadow Ball and Ice Beam can cover Ghost and Grass weaknesses respectively.