Attached Link: http://www.loc.gov/rr/print/list/listguid.html

I've tried searching for blueprints and plans of buildings but have generally gone round in circles searching for free ones. "FREE! FREE House plans!!!" Only to get to the site and find that if I pay $$$$$ I can have my free house plans. :S

I've had better luck using elevation or elevations as a keyword - these are how the building looks from the outside and are easier to translate into a 3D model. Historic buildings and information on restoration seem to give the best results. There are some interesting elevations at the Library of Congress; I particularly like the bungalows and the saltbox houses.

Some of the projects at This Old House have elevations as well as plans - they're small though. There are also picture and 360 tours of certain homes.

A local historical society, local government/planning/archival department or library service may be a useful resource too if you can get access. (Possibly not if you're wanting to make something exotic though.)

Maybe try some architecture/building/CAD forums too if you can track them down. Good luck!

swishy