Of course, there are always the kaiser dragoons to take up one sub slot (not the main!). Although I don't actually what their atk exactly is at 0* (as I've only heard that it's still more than sufficient). But their summon effect is really good. They are the main priority in the eidolon orb shop for good reason. I only leave them out as I don't know when a particular individual should expect to pick one up, as the rate at which you get orbs varies from person to person.