Now that petpages are up and running again you can find images for all the old Maraquan petpets on this page: http://home.neopets.com/templates/homepage.phtml?pet_name=sweetheart_valentina
(Scroll down to the bottom to find them.)

Also according to this site: http://home.comcast.net/~petpets_inc/index.htm
The Gomer turned into a Filamen and the Gulper turned into a Gulper. (Same name but different images.)

According to a text file I have saved to my computer the Swirly turns into a Sproing and the Alfy turns into a Pfish.

The info originally came from posts people had made here at NI.