Psychic scream, shadow word pain, mind blast.
Hunter's do nature damage apart from serpent sting?
As a form of DPS, Hunter never (or at least should never) use Serpent Sting as a form as DPS. ES AND KC in burst. Serpent sting is on beneficial to keep rogues/druids from going into stealth.
In premades, I doubt these hunters would use this. Most of the time you can mark one and kill the other.