Trium's C3 and Pharaoh Utilities System. It can decompress and recompress C3 and Pharaoh saved game files and can retrieve a lot of information (which is primarily what I use it for). There is a C3 desirability calculator.
I am making my little box of tricks available on the clear understanding that much of the software is not of release standard.
Bear in mind I wrote it for me, and I don't need to error check everything for me or cater for every daft thing a user might do since I'm the only one using it.
It's also largely undocumented and not as well organized as I would want for public release.
That said, I found it quite helpful in lots of ways. My last use was counting the number of invading soldiers when writing a walkthrough.