I have just uploaded to Github a Modelica package containing three media definition. One for ideal gases, another for mixtures of ideal gases and the last covering the liquid and the saturated gas phases. You can find it at Title
The ideal gas models have been done as a personal exercise in order to better know Modelica.Media, nevertheless they allow for the use of many different ideal gas heat capacity correlations, extending the use to substances not covered by the Nasa Glenn coefficients.
The liquid/saturated gas model extends PartialTwoPhaseMedia and is based in the use of correlations for fast calculation. It has been developed using OpenModelica 1.13.2, so it is fully compatible. I have enterered data for a few substances, but my point of view is that Modelica files is not the best place to store data. So the data is in a relational database and can be exported in the Modelica format when needed. This is done using a program which Windows executable can be found at Title
I expect to extend the packages in the next future, and it would be good to joint efforts with other people interested.