can i destroy my trophies?
If you already completed Nevermore, there shouldn’t be any reason to keep the items.
If you’re ever in any doubt about what to do with any item you can look it up on the Wiki.
Unless it’s a very new addition to the game (like stuff added in the last update) it should have all of the uses listed.
“Life’s a journey, not a destination.”
In general:
Go to the legendary craftsman Hobbes (or whatever his name is — the one you buy the books from) in Lion’s arch and tell him you want to buy an item you lost. You can destroy any item not listed there. (Note: Items you haven’t gotten yet, won’t be listed, so if you get future trophies, you need to check the list again.)
For items listed there, right click on them and look at the collection. If you finished it, you don’t need that item anymore either.
Finally, if you destroy something you needed, you can always buy them back again from the legendary craftsman for some karma, which you probably have plenty of.
Oh, and you can sell most, but not all, of them for some silver.