Ravensblight has a free paper model of a hearse and coffins. Because you can have your printer resize these, they can be used for any number of scales and games.
Add a creepy cemetary to your tabletop with this paper model from Ravensblight. The file is a pdf, so you cna resize it using your printer’s control panel to make it fit whatever scale you need.
Here’s an interesting concept: Truetype and Type1 Fonts that are sets of wargaming and roleplaying figures instead of letters. Because they are, like all fonts, scalable, you can print them at whatever size you prefer.
Among the font sets are superheroes, pulp adventures, space opera, Ironclaw roleplaying figures, treasure, scenery and starships.
Here’s a paper model of a medieval watchtower in 1:140 scale. The site is in German and the babelfish that I used wasn’t very good in translating it, so I can’t tell you much more. 1:140 scale is probably not good for most miniature wargames, but you could easily scale them up when you print.
Clifford Button of Paper Tiger Armanents offers a free 1/72 scale brick structure. It was inspired by a building in the Strand district in Galveston, Texas.