This is my insert for the Craftsman 10 Compartment organizer that I talked about in this video: https://youtu.be/PbI8XCNjGuE

This will hold 100+double sleeved cards as well as a Boulder 100+. (It won't hold a Prism, they are just a smidge too big)

They fit nicely in the Craftsman 10 Compartment organizer as well as other organizers Craftsman makes of a similar style. (Mileage may vary a bit here but all the ones I've tried work.)