Here are some freebies from PoserDirect.com
Poser Mega City – Block 
Another detailed sci-fi model, this time a distressed model of a tallish futuristic building.
Modelled using Carrea 5 Pro, this Poser prop comes with a small parented side piece you can use to move around to block the background.
Poser French Village
5 building props with high quality textures and modelled add-ons such as drain pipes and cables. All parented to a large ground base with telephone pole and warped pavements. Please refer to the read me as this contains additional information.
Poser Sci-Fi Environment
An incredibly simple to use prop suitable for Science Fiction scenes.
With highly detailed modelled features, with a medium-low polygon count, and carefully UV-Mapped textures. The package also includes 6 assorted parts, 3 preset scenes and templates.