Those Dragons capable of spell craft are unable to enchant Magic items unless they are 9HD. HD range from the medium +/- 3HD. So only the largest Dragons of each type qualify as crafters of magic items. Spells however dont improve with HD as they do in BECMI/Rules Cyclopedia D&D.
Charmed Minions: All dragons capable of a first level spell can charm a minion. Scroll Library & Minor Magic Items: any dragon of 9HD+ can create a scroll library or enchant minor magic items.
Crystal Ball Surveilance: The dragon with access to third level spells can enchant a crystal ball.
Somewhat different from dragons that can animate undeaf and enchant flying csstles.