What word can I use to mean "something which is scavenged?"

I'm looking for something similar in connotation to "curio," "knickknack," or "bauble," but which carries a strong implication that the item was found by happenstance (particularly while looking for something not directly related). I imagine I might remark that an object I keep in my room is "just a _____ I fished out of a flea market" if a friend asks about its origin. Is there a noun so specific?

The Macmillan dictionary defins the noun (as oposed to the verb) find as

something good, interesting, or valuable that you discover by chance

with examples

The statue could be one of the finds of the century.

And

Our new nanny is a real find

This is probably the most common and most widely understood word for something acquired serendipitously.