A box made of paper: Function!
Panorama/Concertina books. With the pages cut into shapes. A simple way to make a concertina book unique.
Children's book: Cutouts in the page show parts of the next illustration (lion through trees), other pages turn over and cover just enough of the previous illustration to show a change (rabbit) .
'Theatre' book: Each double page spread 'pops out' to make a 3D scene.
3D pop-up dinosaur skeleton and octopus:
Anatomy book with a pull tab to show what happens when we breathe in and out.