I’m not sure what you mean by “SNAP processes”.
Maybe you refer to the operators which can be used with GPF.
For the complete list available in you application your can call on the command line ‘gpt -h’
Also there is the API documentation for SNAP. Which is helpful if you want to invoke some SNAP method: http://step.esa.int/main/community/developers/
Most (99%) of SNAP ist implemented in Java. But there are some operators which are implemented in Python