Buzzwole and Rillaboom buth commonly use Drain Punch on their sets. Buzzwole gets STAB, and that plus Bulk Up makes it quite a good user. Rillaboom gets Swords Dance, and that plus a Life Orb can make it do massive damage. Rillaboom does sometimes opt for Superpower, but Drain Punch is a very good choice. Buzzwole sometimes uses Close Combat, but Drain Punch is generally the preferred option.
Hope I helped!