Typically you wouldn’t see fan-made items on the Wiki, but this one deserves an “honorable mention” as being a Super Powers item as it’s extremely well done and very useful for holding your flat Super Powers and related items.
These are high quality 1.5″ 3-ring binders, custom made by Jay (aka abraxis1969). Sometimes they pop up on eBay but Jay has made them available on Mike’s Super Powers runboard forum here: http://bkennersuperpowers.runboard.com/t30157