List all the fonts used within a Photoshop file (PSD). Load the whole file in memory and search for font sets byte by byte. This is not pretty but it works (TM).
This is how it works:
$ psdfontlist myfile.psd OneFont AnotherOne SomeRandomOtherFont
You need Python 3 and you can get the code from the repository below:
https://github.com/tamentis/scripts/blob/master/psdfontlist.py
Then you can run it from there or install it somewhere in your PATH.