I'm doing a design at the moment that incorporates a rather unusual industry: a landscape supply company, the kind with lots of fountains and statuary piled around outside. I was scratching my head trying to think what I would use for all this outside merchandise, and got the answer recently when browsing a craft store: glass or ceramic beads. I will just select the appropriate sizes and shapes, and paint and weather them.
The experience reminded me that all kinds of random bits can be pressed into service on a layout. Look around you, see any ideas?