Drupal 8 successor to D7 Offers & Wants, which supports local communities to share and exchange their stuff and skills.
Ready rolled 'feature' type module allows permitted users to post ads and browse by category.
Smallads is its own entity type which is planned to have a remote storage controller pointing to REST API service. The entity comes with several fields already - image, geolocation, expiry date. Some handy views and blocks are provided also.