A crucial part of any equilibrium modelling calculation is the selection of equilibrium constants that quantify the strength of interactions between metals and ligands. For researchers new to the field of solution chemistry, locating suitable equilibrium constants that lead to reliable model results can be problematic. Numerous large compilations of equilibrium constant values have been published each having their own limitations, coverage and availability. This work surveys eleven major compilations of equilibrium constants including those from authoritative groups such as IUPAC, NIST, and NEA. For each compilation surveyed, details are given related to the historical background and underlying project, scope of the database with respect to range of included metals and ligands, and the present-day availability of publications or computer databases resulting from the project. The various methods employed by different data compilers in their critical assessment for each compilation are also discussed.