I've changed my name for this as it'll make me far too identifiable!
When one of mine was a kitten he began to bring home gardening gloves one summer. We got loads - sometimes pairs, mostly odd ones.
Then winter came, and with it came childrens wooly gloves - no idea where he got them from.
The following summer he progressed from gloves to underwear . He'd raid people's (thankfully clean) washing baskets that they'd left outside, and bring home neatly balled-up socks and knickers, and once a very-expensive-looking blue velvet bra! I thought it was hysterically funny, DH was just terrified that people would think it was him! I used to regularly knock on doors with a bag of clothes asking if it belonged to anyone - oddly enough, everyone always denied ownership!