Is there a list of NMEA 2000 messages (a message is identified by a Parameter Group Number, or PGN)?

Yes, the National Marine Electronics Association (NMEA) publishes a list of PGNs, which can be found via this link:

http://www.nmea.org/content/nmea_standards/messages_pgns.asp

Article ID: 557
Created: October 10, 2012
Last Updated: July 30, 2015
Author: Mark Oslund [mark.oslund@maretron.com]

Online URL: https://www.maretron.com/wp-content/phpkbv95/article.php?id=557