If you search the web for rare Apple prototypes, you'll likely come across the name Hap Plain.

Plain is a private collector in California, with what he describes as the world's largest collection of rare Apple prototypes by a private collector.

Over the last decade, he's amassed a collection of more than 250 unreleased Apple products, like iPhones, iPods, laptops, desktops, servers — and the list goes on.

Plain even turned his collection into profit by selling the items on eBay. In March, Plain listed a rare Lisa 2 prototype on eBay for just under $100,000; however, it caught the attention of Apple's lawyers and has since been removed.

But Plain will continue adding to his collection and hopes some of the devices end up in a museum one day.