I loved this. It brought back such memories.

For what it's worth, we collected loads of "craftable" stuff when my two kids were small. I found a large box full of it in the attic when tidying last year. Stuff like egg cartons, cardboard tubes, cardboard boxes (flattened), washed food trays, lollipop sticks and similar, straws... You get the idea.

Play was with all of these and PVA glue/sticky tape, and sometimes paint. You can bet that all manner of fantastic structures were built.