For grass pokemon, there haven't been any melon based Pokemon, or fruit in general. Closest we got was Tropius, but he's more of a dinosaur. Maybe make a Pokemon that starts out as grapes and evolves into wine, or a Pokemon that starts out as a kiwi and evolve into horned fruit. I dunno. Try that.
For electric, I don't think anyone has come up with the idea of an electric eel. It could be water/electric.