If I've made puff pastry I use the trimmings to make little cheese palmiers or cheese straws.
Just sprinkle with grated parmesan and some paprika or black pepper and shape to your liking then bake until golden. We'll have them with drinks before dinner.
When the children were little I used to make a few jam or lemon curd tarts with left over pastry. Now I would make a quiche or an apple pie with just a top, or an apple tart with just a bottom!