How much will your utilities cost? This is like Zillow for home values: based on aggregate data (an estimate) It's called Utility Score. Click on image for link.
Provides all publicly available records on a home's history regarding building permits and such. I recommend this particularly in homes that seem to have a lot of DYI work: you want proper permits for renovations or you may have to redo them when you sell. Click on image for link.
HowLoud uses algorithmns to estimate how noisy it is near your prosepctive home. Click on image for link.