OneMonk has posted a free paper model of some standing stones and stone blocks that wold useful as a ruined city.
Paper Models
Aerosan Paper Model
Mayhem In Paper offers a free paper model of US and Soviet aerosans — propeller driven sleds.
Papercraft Nativity Set
Schweitzer Comics offers a very nice paper model Nativity Set. It’s not quite free, but it is “pay a fair price.”
Free Dropship Paper Model
Grey Matter Games offers a free paper model of a science fiction dropship, suitable for games from 6mm – 28mm.
Paper Star Trek Miniatures
One Monk offers a set of paper miniatures for Star Trek adventures.