A treasury is the member-curated gallery. If you were featured in a treasury list, it means that someone included your listing in a group or set of listings that they think fit the specific theme they were going for. For instance, one of my treasury lists is "Valentine's Love <3", so I included hats, rings, headbands, napkins, bags, cards, gifts, etc. with a Valentine's theme. Basically it is a themed list where a shopper can go to get a group of similar or similarly-themed items.
Hope this helps!
