These aren’t very rare, but you don’t see collections of them all too often. I bought these in an ebay auction a few years ago; probably overpaid! These are the demo discs that are sent by Nintendo and Microsoft to retail stores to run on their display units.
Here are the Gamecube demos, in full-sized Gamecube cases:
And here are the XBox demos, in small paper sleeves:
I have a few of the Xbox kiosk disks but you seem to have way more.
Gamecube kiosk discs always seemed too expensive to start collective considering how many there are. I’d never undertake collecting such a strange thing as kiosk discs without trying to complete the set, which would cost $100s that could be spent on something much cooler 🙂 I think I have one or two kicking around if you want some more.