I looked at some of the dragon default know lists, and they're often pretty terrible (CL1 burning hands at CR7 on a type that has a reusable fire breath weapon). How do we fix this?
Read Magic (utility)
Detect Magic (utility. If something is magic it's valuable and or dangerous)
Prestidigitation (utility, also things you can't do without hands)
Mage Hand (for fine movements without turning into a humanoid, especially so for those that can't)
Mending (for fixing up loot)
Unseen Servant: Another in the theme of working things intended for small hands. Also general labor fits dragons.
Thunderstomp: You can use your casting stats and casting level instead of BAB and strength. This spell still lets them shake the ground with a stomp with their huge strength and BAB
Truestrike: Same as any gish really.
Blurred Movement/Vanish: Basic defenses
Wizened Appearance: More size is still great even without ability score changes. Also good for a bluff.