I think there is one called ‘fertility calendar’, or ‘my calendar’. It’s not specifically for NFP, but you can enter your start and end cycle dates, and if you are trying to get pregnant or avoid pregnancy. It will tell you when you are ovulating and when you are not. Obviously a bit of guess work, but with a thermometer, you should get pretty accurate results.
EDIT: I mean, if used in conjunction with a thermometer, you should be able to plot your cycle fairly accurately.