The National Institute of Standards and Technology (NIST), the non-regulatory federal agency within the U.S. Department of Commerce, promotes U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology. The agency publishes standards many of which are free, including Ceramics WebBook, Chemistry WebBook and Physical Reference Data. To satisfy your curiosity, check out the complete list at the NIST Data Gateway, and get to know your standards.