I am trying to get a "Dyeable" tag added to items on Console, the same way it is shown on TERA PC, which should make it easier to tell which ones are eligible.

Right now, the majority of items that can be dyed have the word "Dyeable" in the name, and you will see an option to press Triangle (PS4) or Y (Xbox) to bring up additional options, one of which will allow you to apply an Apothecary Dye.