Vestiaire Collective offers a wide selection of both vintage and current-market resale. The company is unique in that the seller is responsible for creating their own listing (and keeps their item until it's sold), but the item and pricing have to be accepted by Vestiaire before the listing goes live. Additionally, for buyers' peace of mind, sold items are first shipped to the company for authentication before they are passed along to the winning bidder.
Image Source: Courtesy of Vestiaire Collective