Am I not loading all of this article? It basically stops for me after saying "magnet toys top the list" with 3 examples of such (well, really 2) for me, with no real investigation into other toys or exploration of why the variants like the Minecraft magnet toy scored much worse in cleanup (I assume it's due to the piece size?). Anything about toys other than magnet blocks?

Another type of toy I've seen fit this bill has been wooden/plastic train tracks (the solid larger pieces type, not flimsy model type, and simple sturdy trains to go on them). It still has the element of customization and playing with what you build but cleanup is "scoop the large pieces into a bucket" (and stepping on them usually isn't painful!)