based on an earlier version of the Wolfram Language.
ElementData — bulk, atomic, chemical, etc. properties of chemical elements
ChemicalData — structural, physical, and other properties of chemical compounds
IsotopeData — static and decay properties of all nuclear isotopes
ParticleData — properties of stable, unstable, and resonance particles
WeatherData — full current and historical worldwide weather data
GeodesyData — data on geodetic coordinate systems, geoid shapes, etc.
AstronomicalData — static and dynamic properties of stars, planets, and other objects
GenomeData — properties of human and other genes
GenomeLookup — fast lookup of human and other genome sequences
ProteinData — protein structure and function