Three boxes from the "Curios And Conundrums" subscription series from the Mysterious Package Company: "Countdown to Oblivion," "The Brain Butchers" and "Clockwork Mutineers." Two of the boxes ("Countdown to Oblivion" and "The Brain Butchers") have been opened and seem to be complete. "The Clockwork Mutineers" is still sealed and is also presumably complete. All of the boxes have slight wear, but the items in the boxes are like new.
This description from the Braingle website describes these puzzles and recreates the Vault where solutions could be found: "Curios And Conundrums was a quarterly mailing from the Mysterious Package Company that contained puzzles as well as interesting artifacts and stories. It ran for 4 years with back issues sometimes available for order through their website.
Volumes 1-3 contain very difficult puzzles. The puzzles usually contain several layers, so after solving the surface level puzzle (like a crossword), you would have to find the answer to the meta puzzle. Then, there was usually a 3rd layer puzzle that you could solve by combining two puzzles or by solving the original puzzle in a different way. All answers could be checked by entering them into "The Vault" which was a special section of the Mysterious Package Company's website. The Vault would often give other puzzles that needed to be solved. If someone was able to solve every puzzle, then they could open The Vault. A year after Volume 3 was released, only 87 people had opened the Vault. Do you have what it takes?"