Equilibrium constants for any reaction from optimised species G0 values.
You can inspect the 'JESS Thermodynamic Database'. It currently contains:
We appreciate feedback, especially notification of errors. Reprints with data that we have not yet included are most welcome.
There are ancient cathedrals which, apart from their consecrated purpose, inspire solemnity and awe. Even the curious visitor speaks in hushed voice. The labor of generations of architects and artisans has been forgotten seeing only the perfection of the whole ... the result of giving ordinary human effort a direct purpose. Science has its cathedrals, built by the efforts of a few architects and of many workers ... (such) is the edifice of thermodynamics.
G.N. Lewis and M. Randall (cited by R.E. Mesmer in Proc. 5th Int. Symp. Hydrothermal Reactions, p. 1)