Mmm... [ The noise is one of consideration, as is the frown. Trickier question, but not at the same time. ] I suppose... When you consider that all magic relies on aether and the manipulation of it, one could argue that the disciplines themselves are specialties. It isn't very common but there are some exceptional individuals who can find ways to make even those specific types of magic their own.

[ Y'shtola immediately springs to mind, as does Master Matoya.

Ziva sets down her device so that it's propped on a table against something, freeing her to fold her arms in thought. ]

The disciplines had to start somewhere as well, so perhaps those that created magic as we know it today could have been considered specialists, once. But if you want the straight answer, then no. Magic is relatively uniform in practice. Red Mages practice a mix of black and white magic. Black mages specialize in destruction spells. Conjurers and White mages are healers with very few offensive capabilities. Astrologians draw on the influence of the heavens for theirs. I've not yet heard of any individual with a type of magic wholly unique to themselves. The nearest I can think of are Arcanists, who I believe are said to have once had two branches of specialization.

[ But my player ditched the SCH/SMN job two expansions ago so we don't know about that IC'ly. ]