Is your feature request related to a problem? Please describe.
No

Describe the solution you'd like
It'd be nice to filter out specialty professions.

Additional context
For example, in Leatherworking, There are filters for Leather or Mail and then filters for Back, Chest, Feet, etc. Can you add a filter for Dragonscale, Tribal, Elemental, and then whichever the other specialties are for the other professions?

hmm yes I think about what's the best way to implement this

I hope the two files attached properly. I took a look at the code. I believe the change is pretty simple. The PNG is my end result on adding Dragonscale to the list for Leatherworking. The TXT is the code I used. I just added it at the end of the Leatherworking section after Misc (in data.lua). I believe if this were to be added for each of the specialties, it would be a great addition to your add-on.

Also, I checked the leather chest, leather feet, etc. and the Dragonscale pieces are still listed, so adding another sub-section does not affect the others.

Only other thing to note, I just listed the material as Normal rather than Mail since there's only one material used for this specialty.

Dragonscale.txt

Yup, that is a good change. This could be submitted as a working PR.