The National Institute of Standards and Technology (NIST) hosts a variety of different reference datasets freely available to the public. We have picked two databases that could prove useful to you!
Chemistry WebBook
A database currently consisting of organic compounds along with a few small inorganic compounds and data on thermochemical, thermophysical, and ion energetics.
Besides the usual search fields, you can search the WebBook for formulas, reactions and structures, as well as making physical property based searches.
Some useful models and tools are also included:
Solubility Database
A database aiming to give a comprehensive review of published data for solubilities of gases, liquids and solids in liquids or solids.
The data on solubilities was originally published in the IUPAC and contains over 67,500 solubility measurements, 1800 chemical substances and 5200 chemical systems.
Access more of NIST’s standard reference data here.