Many of the items that come through the thrift shop are mysterious in origin and purpose. We could have transfer boards possibly no one knows what they are. Or, they arrived in such bad shape that while perhaps being usable to you, are considered unsellable by the store. But yes, it's completely random. :-)
As a thrift store, their inventory is entirely dependent on what is donated. They don't stock anything, so i wouldn't expect to find transfer boards.
Thanks! Your answer is awaiting moderation.