u/Deciduorn

I recently found the transmuter in Tyrhold and read up about how certain raid appearances for the Dragonflight raids are only obtainable through transmutation? Is there a resource anywhere where I can see what pieces for each class aren't obtainable via drops and are only obtainable through transmutation? I have been getting pretty bad duplicate drops from Amirdrassil and Aberrus when I do my weekly mythic solo transmog runs and I wonder if this might be why?