crawdaunt can learn rock slide, which is a physical rock move, and if you go with starmie, it can learn thunderbolt. Carvanha can learn ice fang at lv. 16 which in turn moves on to sharpedo, and crunch. That would essentially take care of psychics and ground types together, so i recommend sharpedo, plus the added damage of roughskin hurts physical sweepers, crawdaunt can also learn crunch later, and ice beam for an ice type move (although sharpedo and starmie both get ice beam as well) and starmie could learn signal beam for psychics, and ice beam for ground types, plus a resistance to psychic, (although sharpedo and crawdaunt have immunity to psychic...) also staryu learns power gem, a rock type move, at level 46 if you're willing to train that high. but if you chose starmie, you would be best off as a special sweeper for both. My first recommendation: Sharpedo. Best physical moveset, and roughskin hurts contending physical sweepers. Crawdaunt i suppose gets guillotine, but it lacks a move like lock-on to garuntee a hit.