A sidearm shotgun (Possibly a sawed off double barrel) that takes up the pistol shot would be fun. having no sight attachment, but can have a choke, laser sight, and possibly Unique Rounds as an attachment. Such as buckshot, Flechette rounds, Dragons breath (lower initial damage but damage over time to be a sort of way to counter healing, or reduces healing taken for a while), to make more dynamic builds or weapon choices in the secondary slots.