Phillip Fickling has a paper model of a submarine that may be of use for victorian science fiction fans. Click on the free model link.
The Mazes and Minotaurs Yahoo Group has in their downloads section a nice set of paper miniatures of Greek Heroes, Gods, and Monsters.
This three story european paper building model looks like it would work pretty good for 15mm miniature wargames. Players of Flames of War should take a look and see if it fits in with their tabletop layouts.
The Paper Model directory has a collection of links to dozens of paper car models, from DeLoreans to Hondas. These are just what you need to populate the streets of your modern era miniatures wargames. As is usual with these, you can use your printer settings, graphics program (that’s what I use) or a copy machine to adjust these to whateve scale you need.