Guild Wars 2

Hello everyone, I now is collect the legendary collection, so I just finish 1 of 15 and get a trophy in my bag, do I need to keep all of them or just sell its?

You can use the Wiki (link above) to look up any item and determine its possible uses (or lack thereof).

Good luck.

If its just a trophy, you can sell it to the vendor once it is lit up in the collection achievement in your hero panel (eg nothing else in the label such as crafting professions)

Yes, the Collection Trophies are useless once they have been added to the collection (please double-check if the item has been added and doesn’t have any further purpose).