Here's an idea for a miniature wargaming scenario: During WWII, a group of US paratroopers, or British commandos are sent to destroy a V-2 rocket base. Of course, to do this, you're going to need to add a model of a V-2 rocket to your terrain. This website has a free paper model of a V-2 rocket in 1/32 scale. You could easily rescale it on your computer.
Matt Fritz has some advice on printing and basing paper soldiers for your miniatures wargames.
There has been a surge in interest in playing "Battles by Gaslight" in 15mm scale. No steampunk miniature wargame would be complete without a land ironclad or two. This 15mm Land Ironclad paper model fits the bill. It is based on one portrayed in a 1903 short story by H.G. Wells. From Ralph Currell.
Wizards of the Coast has this free 25mm - 28mm wargames model of Intact and Ruined City Walls.
Wizards of the Coast has this 25mm - 28mm papermodel of a medieval cottage. You could print out a whole bunch of these and have a whole village for your miniature wargames skirmishes.