The piece kept because it is unusual may eventually reveal what the whole collection is about.

The odd item you kept without a reason is often the honest one. Everything else was chosen to fit a pattern you already understood, while the outlier came from an interest you had not yet named. Looking back, the exception frequently explains the rule, because it shows what you were actually drawn to before you had a category for it.

Look at whatever you have gathered without meaning to, whether that is books, saved notes, or projects you started. The one that does not belong is worth a few minutes of attention, since it may be pointing at the thing the others were circling.