There was an Addon that is not updated long ago that has very nice functionalities for you think about it and maybe...only maybe implement a few in the future. The addon is called Legion Wardrobe and here are the features I'm talking about... and I put the ones I think are really good in Bold for you to check

A lot more info about items that offer appearances (links to wowhead, names of vendors, costs, world drop zones, etc)
Additional info about collected appearances on items tooltips
Current quest zone, current instance, current raid filters
Also you can filter any zone or raid to view all appearances that you can collect
You can press TAB button, when you hover item for view info about all sources for that appearance (only for items that available for your current class)
Sets page that shows your current progress on collecting appearances sets
Option to "Find all recolors"
Selecting favorites for uncollected visuals
Custom camera for preview buttons
Message that new appearance was learned (for blue and green items)