Located in the vast depth and breadth of government websites are free software programs that anyone can download and use.
No, you can’t sell them, but you can use them for your own purposes.
No one knows more about anything than the U.S. Government and they don’t mind spending our money to find out and develop many software products. This isn’t software for free money and other worthless stuff. This is software that you can actually use and benefit from.
Take for instance the USDA’s Body Mass Index (BMI) or their SuperTracker; as well as the Department of Energy’s Building Energy Optimization tool (BEopt). Or the USGS’s Planetary GIS Web Server (PIGWAD).
The links either go to the online or download version. If a list of software could be found on one page – I have linked to that page – if not, the software is individually linked.
The information is listed by department, bureau or agency.
Have fun looking and using.