Ravensblight Manor is a free paper model of a haunted house. I took a look at it, and think that it would be just about the right size for 25mm – 28mm figures.
paper model
Mines of Moria Paper Model
Here’s a nice set of paper model walls, columns, corners and stairs for constructing your own Mines of Moria.
Starfighter Paper Models
Genet Models offers two free paper models for starfighters and a model of an orbital missile gunboat.
Jungle Hut Paper Model
For your jungle games, here’s a paper hut model.
Post and Rail Fence Model – Grey
I’d previously posted a file of traditional post and rail fences — suitable for the American Revolution and American Civil War — in brown. For a more weathered look, I created another file where the rails are a greyish color.