Trough /tgh command you can print full livetime history list to default log of all gathered items whatever you anytime selected it or not...
You can very easy select only that mats or gathered items what you are interested.
You can See gathered information everywhere in the game, in the profession window, Auctioneer, bank, bags in logs...
Everytime you loot, you can see if any looted item is tradable or craftable. Only you need switch ON this all futures in option menu.